■
0^7?z&Z /7 (£p.! ')•' r. , | iv ^rr-f ^(W. ^ ^ lUaa^ l|rtri^ IAf-^4,^ ^ ^Ui ‘^wrus/tyv dp til \o*£ ' . OMY OF THE HUMAN BONES AND NERVES, WITH A DESCRIPTION OF THE HUMAN LACTEAL SAC AND DUCT, BY ALEXANDER MONRO, M.D. FORMERLY PROFESSOR OF ANATOMY IN THE UNIVERSITY OF EDINBURGH. CAREFULLY REVISED, WITH ADDITIONAL NOTES AND ILLUSTRATIONS, 9nlf a gmjiplmfnt, CONTAINING A DESCRIPTION OF THE INTERNAL EAR, By JEREMIAH KIRBY, M.D. AUTHOR OF “ TABLES OF THE MATERIA MEDICA,” &C. FOURTH EDITION. EDINBURGH : PRINTED FOR BELL AND BRADFUTE, AND ADAM BLACK, EDINBURGH; LONGMAN, REES, ORME, BROWN, AND GREEN, AND JAMES DUNCAN, LONDON. M.DCCC.XXVI11. I CONTENTS. Letter to Dr. Barday Pagevii Introductory View of Barclay’s Nomenclature . . xi Tables of the Bones of the Head .... xviii Table of Reference to Mitchell’s Engravings, as Illus- trated by Dr. Barclay ..... xxvii Author’s Prefatory Address to his Pupils . . . xxix The Anatomy or the Human Bones ... 1 Of the Bones in General . . . ib. Of the Skeleton . . .43 Of the Head .... 44 Of the Truuk . . .119 Of the Superior Extremities . 166 Of the Inferior Extremities . 196 Appendix. Of the Marks of a Female Skeleton . . 222 The Anatomy of the Human Nerves .... 225 Of the Nerves in General . . ib. Of the Particular Nerves .... 256 Description of the Homan Lacteal Sac and Duct . 284 Supplementary Description of the Internal Ear . 287 2 TO ALEXANDER MONRO, M. D. FELLOW OF THE ROYAL COLLEGE OF PHYSICIANS, AND PROFESSOR OF ANATOMY AND SURGERY IN THE UNIVERSITY OF EDINBURGH, &C. &C. Sir, I beg leave to present you with a new Edition of your respected Pre- decessor’s invaluable Work on the Anatomy of the Human Bones and Nerves. In preparing this Edition for the press, I have been anxious only to render the work more generally useful to Anatomi- cal Students of the present day, by adding to it a few references to later authors, who have treated on the same subjects, and some synonymous names and terms, which may be more familiar to certain classes of readers. The matter of the excellent ori- 3 VI ginal has been left unchanged, except in a few instances, where alterations were war- ranted by the quarto edition of the Author’s Works. The changes which have been occasionally made on the language> were also suggested by the same edition ; and if, in this particular, I have presumed to go beyond the Editor of that collection, it has been merely with the view of accommo- dating the phraseology to the fastidious delicacy of a modern ear. I have the honour to be, With the greatest respect, Sin, Your most obedient humble servant, J. KIRBY. Bdin. Nov. 1820. TO JOHN BARCLAY, M.D. FELLOWOF THE OF ROYAL THE ROYALSOCIETY, COLLEGE AND LECTURER OF PHYSICIANS, ON ANATOMY FELLOW AND SURGERY IN EDINBURGH. My Dear Sir, It is now about ten years since I was induced, chiefly in compliance with your persuasion and advice, to superintend a new edition of Monro’s Anatomy of the Human Bones and Nerves. Your pupils are early taught, both by your pre- cepts and your example, to see the importance-— the necessity—of acquiring an intimate and cor- rect knowledge of Osteology, before they can pro- perly comprehend, or apply to practical purposes, the other departments of Anatomical Science. From the respect which they frequently hear you express for the Osteology of Monro, as well as from the acknowledged intrinsic merit of the work itself, which has procured it a place, either in whole or in part, either in its own proper dress, or under various masquerade habits, in almost all the Anatomical Systems, Treatises, and Compen- diums, which have appeared in this country, they are naturally led to prefer the original work to all the writings on the same subject that are continu- ally teeming from the press. Till That your opinion of the permanent populari- ty of this truly Classical Work has been well found- ed, sufficiently appears from the rapid sale of the two former editions, and the reiterated call for another. Again invited to the agreeable task of ushering to the public this New Edition, I can- not allow so favourable an opportunity to escape of addressing to you my introductory observa- tions, on the nature of the Original Work, and the circumstances which characterize the present Edition. Excellent as the matter of Monro’s Anatomy of the Bones confessedly is, it cannot be denied that something was wanting to accommodate it to the improved state of Anatomical knowledge, which, in the other departments of that Science, distinguishes the beginning of the nineteenth cen- tury. The language of the Original, though per- spicuous, and in general correct, is often antiquat- ed, and therefore ill-suited to the refined taste of the present day ; and the references to other au- thors were so far incomplete, as not comprehend- ing those subsequent to the Author’s time. Mon- ro’s names of muscles, too, though well understood in the early part of the eighteenth century, are now, in general, become obsolete; and the No- menclature of Anatomy has, chiefly through your means, received such important improvements, that in a few years many of the old terms for po- sition and aspect will either be abandoned, or will not easily be understood. To supply these obvious defects in the work ix which I have undertaken to revise, has been my principal object in the two former editions, and more especially in the present. I have, in many places, modernized the language ; given addition- al references to later authors on the same subject; added the synonymous names of muscles of Albi- nus and Innes; and, wherever the old terms for po- sition and aspect might be productive of ambigui- ty or obscurity, I have pointed out, in foot notes, the terms of your Nomenclature with which they correspond. * Although both from your own writ- ings and those of your disciples and converts, these terms are now better understood, than when I published the former Editions, I have thought it advisable to retain the short account and Tabu- lar Outline of your Nomenclature there given. I have also availed myself of your permission, to add to the Introductory matter, the Tabular View of the Bones of the Head, employed and recom- mended in your Lectures. You will observe, Sir, that in that part of the volume which comprehends the Anatomy of the Nerves, the new Notes and Illustrations are pro- portionally more numerous. This was rendered necessary from the circumstance that many valu- able works on the Nervous System have appeared since the days of the first Monro ; and though they cannot detract from the original merit of the Treatise, they render it comparatively less perfect than the Anatomy of the Bones. At the same by *the The letter Notes E. and References by the Editor are distinguished X time, as I could not, without greatly increasing the bulk and price of the volume, give any de- tailed account of the modern improvements in Neurology, I have been obliged to confine my- self, in most cases, to general reference. In the present Edition, I have endeavoured to supply a manifest deficiency in this otherwise com- plete Osteology, by giving a short supplementary view of the Cavities and Contents of the Os Petro- sum ; and to render my description more intelligi- ble, I have referred to Mr. Mitchell’s late Engrav- ings of the Bones, which, with your Explanations, are calculated so well both to illustrate the present work, and to facilitate the study of Osteology. I once proposed referring, in the same manner, to these Plates, under each bone described ; but this would have so multiplied the foot notes, that I was compelled to content myself with giving a Ta- ble of Reference to them in the Introduction. I cannot but congratulate the Students of Ana- tomy, upon the assistance they will derive from these elegant Engravings, which conveniently sup- ply a desideratum long felt by the readers of Monro. I have the honour to be, My Dear Sir, With much esteem, Your obliged and faithful friend and pupil, J. KIRBY. Edinburgh, Nov. 1820. INTRODUCTORY VIEW BARCLAY’S NOMENCLATURE. It had been long and justly regretted, that the usual terms of Anatomy, implying position, aspect, and direction, were so vague and indefinite, as to be productive of much ambiguity and con- fusion in anatomical descriptions ; for, as the aspect of any part of the body must vary in every different position in which this happens to be placed, no term, that is adapted exclusively to any one position, can with propriety be employed as applicable to the rest. Thus, what is superior in one position of the body, be- comes anterior in another, posterior in a third, and even inferior in a fourth; what is external in one situation (as of the arm and hand,) is internal in another, Ac. If these terms be sub- ject to such ambiguity in describing the structure of the human body, they become much more ambiguous when applied to Com- parative Anatomy. A part or organ which is superior or infe- rior in man, becomes anterior or posterior in quadrupeds, while anterior or posterior in the former is in the latter superior or inferior. The advantages of a Nomenclature, in which the same terms should universally apply to the same organ, in all positions of the body, and in all animals, scarcely require to be pointed out; and we think that those advantages belong to the Nomenclature late- ly proposed by Dr. Barclay. Xii INTRODUCTORY VIEW OF The terms of this Nomenclature are derived from parts of the body which are found in most vertebral animals, and being fixed and determinate, can never confound or mislead. Some of these terms are general, applying indiscriminately to every part of the animal body; but most of them refer to some particular region or organ. Of the yeneral terms, the most universal, and perhaps the most useful, is that which respects an imaginary plane supposed to be drawn vertically through the middle of the body, so as to divide it into two equal and similar halves. This is called the mesial plane; and that surfece of a part or organ which looks toward this plane is said to be mesial, or to have a mesial aspect. Those which are situated in the opposite direction, or on either side of the plane, are lateral, being dexiral or sinistral, according as they lie to the right or left of the mesial plane. Instead of external and internal, usually applied to denote the surface and the deep-seated parts of an organ, Dr. Barclay em- ploys peripheral and central; the former denoting the aspect or position at or next the surface, the latter those next the centre of an organ or of the body in general. The particular terms refer to the head; the trunk; the ex- tremities ; and the sanguiferous system. The terms referring to the head, are derived from the corona or top of the head ; the base of the skull; the inion, or most protuberant part at the back of the head ; and the glabella, or space between the eye-brows. The aspect or position of those parts next the corona are coronal; that of those next the base, basilar ; that of those next the glabella, glabellar; and that of those next the inion, inial. The glabella is not at the greatest recti- lineal distance from the inion, a distinction which belongs to the chin in man, and the muzzle in most inferior animals. These parts are called by Dr. Barclay antinion, and the aspect or posi- tion that regards them is called antinial. The terms proper to the trunk are also four ; derived from the sternum or breast-bone ; the dorsum or back ; the atlas or first vertebra of the spine; and the sacrum or rump-bone. Ac- cording as parts or surfaces respect one or other of these fixed points, they are sternal, dorsal, atlantal, or sacral. The extremities are atlantal or sacral, according as they are situated next the atlas, or next the sacrum. Each pair of the BARCLAY S NOMENCLATURE. Xlll extremities, and each of their component parts, have a proximal and a distal end ; the former being that nearest the trunk, the latter that which is most remote from it. Four proper terms belong to the atlantal, and as many to the sacral extremities. Thus, as the former have a radius, an ulna, an ancon, (or olecranon,) and a thenar (or palm) ; so in these the as- pects and positions are radial, ulnar, anconal, and thenal. Again, as in the sacral extremities, there are a tibia, a fibula, a rotula, and a poples (or ham); so the aspects and positions here are tibial,fibu- lar, rotular and popliteal. The term volar, in the atlantal extre- mities, is restricted, as in common anatomical language, to the parts within the palm of the hand; while planter, in the sacral extremities, is in like manner restricted to those within the sole of the foot. Thus, the teims proposed by Dr. Barclay for position and as- pect, are in number twenty-three, viz. Five peculiar to the head; coronal, basilar, inial, glabellar, and antinial. Four to the neck and trunk; atlantal, sacral, sternal, and dorsal. T wo common to the head, neck, and trunk; mesial, and lateral. Four peculiar to the Atlantal extremities ; radial, ulnar, anco- nal, and thenal. Four peculiar to the sacral extremities ; tibial,fibular, rotular, and popliteal. Two common to both sets of extremities ; proximal and distal; Two common to the whole body and all its parts, peripheral and central. The terms which have just been enumerated, are adjectives, re- ferring only to position or aspect. They may, if requisite, be con- verted into general adjectives, by changing al or ar into en. Thus radien, ulnen, tibien, fibulen, will denote something belonging to the radius, ulna, tibia, or fibula. They may be converted into adverbs, denoting direction, by changing al or ar into ad. Thus, mesiad implies direction towards the mesial plane ; lateral, the opposite direction, or sideways ; at. lantad, towards the atlas, in common language upwards ; sacrad, towards the sacrum, or downwards; glabellard, stemad, and rotu- lad, imply directions synonymous -with forwards ; and iniad, dor. sad, and popliteal, imply directions analogous to backwards. INTRODUCTORY VIEW, &C. The sanguiferous system, in warm-blooded animals, compre- hends two distinct sets of cavities and vessels; the one set des- tined to convey the blood to the lungs, for the restoration of those principles or properties, which it had lost during the general cir- culation ; the other to distribute the blood, after having been thus renovated in the lungs, to the general system. Hence the former set, including veins, a sinus, an auricle, a ventricle, and arteries, are, in Dr. Barclay’s Nomenclature, denominated pulmonic, and the blood which they contain, and which is of a dark colour, is termed pulmonic blood. In the same manner, the latter set of organs, comprehending also veins, a sinus, an auricle, a ventricle, and arteries, are denominated systemic; and the florid blood which they contain, is termed systemic blood. It may be proper to remark, that the merit of this nomencla- ture consists, not in the novelty of the terms, but in the more precise and definite application of terms long in use among ana- tomists, but hitherto employed in a manner so vague and ambigu. ous, as to mislead the learner in Human Anatomy, and be almost wholly inapplicable to Comparative. As the terms are drawn from parts long known and described^ in anatomical works, a knowledge of those parts once acquired leads to the ready appli- cation and use of the terms. They are the more easy of appre- hension to the anatomist, as being accommodated to an established custom among anatomical writers, of describing the body and its parts as a cube or six-sided figure, whose surfaces point upwards, downwards, backwards, forwards, to the right and to the left; and whose parts are situated towards the circumference, the cen- tre, or an imaginary plane, dividing the body into similar halves. It is this imaginary plane which has furnished the only strictly new aspect in Dr. Barclay’s Nomenclature. The uses and advantages of many of these terms will be illus- trated by the notes to the following pages ; but to render them more familiar, tve shall here contrast them with the usual terms in the following Tabular Outline. TABULAR OUTLINE OF BARCLAY’S NOMENCLATURE. ” §1|I TABULAR VIEWS OF THE BONES OF THE HEAD. The Editor is persuaded that the following Tables will be highly acceptable to the young Student, who has any genuine taste for Anatomy. They are extracted princi- pally from Dr. Barclay’s Lectures on the Skeleton, and are well calculated not only to facilitate the means of acquiring a more minute and accurate knowledge of the Structure of the Head, but suggest a mode of establish- ing new and specific distinctions in Natural History, and Comparative Anatomy, and of ascertaining, with the celebrated Cuvier, the particular Species of Fossil Heads. BONES OF THE HEAD. BonesThe ofbones the ofCranium the Head and Bonesare divided of the byFace. Anatomists into tainingThe Bonesthe Brain; of the all Cranium the rest are belonging those of to the the cavity Head con-are the bones of the Face. singleThe andBones four of in the pairs. Cranium are eight in number; four ton,The are four in thesingle, middle like betweenall the single right Bones and left,of the and Skele- each divisiblebones are into termed similar Ossa halves Symmetrica. by the Mesial Plane. These andThose are Ossa in pairs Paria. are upon the sides towards right and left, The Single Bones are. The Ethmoidal,Frontal, The Occipital.Sphenoidal, and Those in Pairs, The two ParietalTemporal. and BONES OF THE HEAD. xix whatThe are Bones denominated of the theFace, Ossa not Plana reckoning and Superior the Teeth, Spongy, nor whichThe are two parts Malar, of the Ethmoidal, amount to fourteen : The two Palatal,Superior Maxillary, The two Nasal,Lacrymal, / The twoVomer, inferior and Spongy, The Lower Jaw. II. theThese Frontal, Bones, the withEthmoidal, the assistance and Sphenoidal, of three of constitutethe Cranium, the five followingThe two cavities: Orbits. The twoMouth. Nostrils, and FORMATION OF T HE ORBITS. Seven enter into the formation of each orhit: The Ethmoidal,Frontal, and AThe Malar. Sphenoidal into the formation of both; A Palatal,Superior and Maxillary. A orbitLacrymal, of its eachside. into the formation of the FORMATION OF THE NOSTRILS. Nine enter into the formation of each nostril: The Ethmoidal,Frontal. The VomerSphenoidal, into theand formation of both ; A Nasal,Palatal, A superiorLacrymal, Maxillary, and Antheir Inferior own side.Spongy are confined to the Nostril of FORMATION OF THE MOUTH. concealedExclusive at theof thetime teeth of Birth,which twentyare wanting, in number or at when least BONES OF THE HEAD. they are temporary, and thirty-two when they are perma- nent,are six. those which enter into the formation of the mouth TheThe twotwo Palatal,superior Maxillary, ThePterygoid lower Jaw, processes and a ofvery the smallSphenoidal. portion of the III. From the preceding statement it appears, that some of theseothers bonesenter intoare theconfined formation entirely of several.to one cavity, and that OF THE BONES OF THE CRANIUM. Five areThe entirely two Parietal, confined to the Cranium: The twoOccipital. Temporal, and TheThe other Frontal, three, The Ethmoidal,Sphenoidal, andenter into the formation of the two ofOrbits, the Sphenoidal the two Nostrils; into that andof the a verymouth. small portion OF THE BONES OF THE FACE. The two Malar are confined to the Orbits. The two LacrymalSuperior Maxillaryto the Orbits and andthe Nostrils.two Palatal, to the TheOrbits, Vomer, the the Nostrils, two Nasal, and theand Mouth. the two Inferior Spon- Thegy, Teeth to the and Nose. the Lower Jaw entirely to the Mouth. IV. to Thethe difl'erentBones of aspects the Head which may they also occupy, be arranged all the according parts of thewere human cubes, andbody had being each viewed six sides by or anatomists six different as ifaspects. they The aspectsThe Coronal,of the Head are, The Basilar,Inial, The orGlabellar, Lateral. or Antinial, and the two Temporal BONES OF THE HEAD. xxi ASPECTS OF THE CRANIUM. The EthmoidalThe Basilar. is confined to one aspect,— The Sphenoidal extends to three,— The twoBasilar, temporal and or Lateral. The Frontal to five,— The Basilar,Coronal, The twoGlabellar, Temporal and or Lateral. The Occipital to two,— The Basilar.Inial, and The ParietalThe Coronal, each to three,— AThe Lateral Inial, orand Temporal. The Temporal each to two,— ^ TheA Lateral, Basilar. and ASPECTS OF THE ORBITS. TheAspect, Frontal and Bone a small forms portion the greatest of their part Lateral of their and Mesial.Coronal Thea smallEthmoidal, portion a oflarge their portion Basilar. of their Mesial Aspect, and Thea smallSphenoidal, portion a of large the portionCoronal of and the Inial. Lateral Aspect, and Theportion Malar, of thea large Basilar. portion of the Lateral Aspect, and a TheAspect, superior and Maxillary, a small portion the largest of the portionMesial. of the Basilar The Palatal,Lacrymal, a very a portion small ofportion the Mesial. of the Basilar and Mesial. ASPECTS OF THE NOSTRILS. The Frontal Bone forms a portion of their Coronal and TheGlabellar Ethmoidal, Aspects. of their Coronal, Mesial, and Lateral. The Nasal,Sphenoidal, of the of Glabellar the Coronal, or Antinial. Inial, and Lateral. The Lacrymal,Superior Maxillary, of the Lateral. of the Lateral and Basilar. xxii BONES OF THE HEAD. The inferiorVomer, ofSpongy, the Mesial. of the Lateral. ASPECTS OF THE MOUTH. The superior Maxillary constitutes a portion of the Late- Theral, inferior Coronal, Maxillary, and Antinial of the Aspects. Lateral and Antinial. AThe small Palatal, portion of theof the Coronal. Pterygoid Processes of the Sphenoi- Thedal, Teeth, a part a ofpart the of Coronal, the Lateral and twoand Antinial.Lateral. V. In different Species these Bones vary their forms, their numberaspects, bytheir which number they ofenter connexions, into the andformation the mode of these and portantdifferent specific cavities; distinctions, and hence which, become in a Naturalsource ofHistory those andim- certainingComparative the Anatomy, species of areFossil so Heads.useful and necessary in as- THEIR GENERAL CONNEXIONS. The Frontal is articulated with four of the Cranium: The twoEthmoidal, Parietal. and WithThe eight Sphenoidal. of the Face: The two Nasal,Malar, The two superiorLacrymal. Maxillary, and The Ethmoidal with two of the Cranium: The Frontal,SphenoidaL and WithThe nine two of theLacrymal, Face: The two superiorNasal, Maxillary, The twoVomer. Palatal, and The SphenoidalThe two Temporal,with seven of the Cranium: The twoFrontal, Parietal, The Ethmoidal.Occipital, and BONES OP THE HEAD. xxiii With seven of the Face : The two Malar,superior Maxillary, The twoVomer. Palatal, and The TheOccipital two Parietal,with five of the Cranium: The twoSphenoidal. Temporal, and WithThe none Atlas. of the Face, but with one of the Vertebrae : The Temporal each with three of the Cranium: AThe Parietal, Occipital, and WithThe two Sphenoidal. of the Face : AThe Malar, inferior and Maxillary. Each Temporal, contains, besides, in its cavity called the Tympanum,Os Orbiculare, four and small the Stapes.bones, the Malleus, the Incus, the The Parietal each with five of the Cranium : The Frontal,Occipital, AThe temporal, Sphenoidal, and WithIts fellownone of of the the Face. opposite side. VI. CONNEXIONS IN THE ORBITS. Thethe Frontal, Orbits withf see sixits : general Connexions,) articulated in The Sphenoidal,Ethmoidal, The two Malar,Lacrymal, and Theed Sphenoidal,in the Orbits f seewith its six: general Connexions,) is articulat- TheThe Frontal,Ethmoidal, The two PalatalMalar, xxiv BONES OF THE HEAD. Thein Ethmoidal,the orbits with (see seven:its general Connexions,) is articulated The Frontal.two Lacrymal, The twotwo Maxillary,Palatal. The superior Maxillary, in its general Connexions, is arti- culatedIts withFellow, ten: The Ethmoidal,Frontal, AThe Malar, Sphenoidal, A Nasal,Lacrymal, AnA Palatal, inferior Spongy, and In Thethe OrbitVomer, with besides four: eight Teeth. The Ethmoidal,Sphenoidal, A Lacrymal.Malar, and Thesix: Palatal, in its general Connexions, is articulated with TheIts Fellow, Ethmoidal, AThe Superior Sphenoidal, Maxillary, AnThe Inferior Vomer. Spongy, and In Thethe OrbitEthmoidal, with three : AThe Maxillary. Sphenoidal, and Thewith Lacrymal, four: in its general Connexions, is articulated The Frontal,Ethmoidal. AnA Superior inferior Maxillary,Spongy. In Thethe OrbitFrontal, with three: TheA Maxillary. Ethmoidal, and BONES OF THE HEAD. XXV Thefour: Malar, in its general Connexions, is articulated with AThe Temporal, Frontal, AThe Superior Sphenoidal, Maxillary. and In Thethe OrbitFrontal, with three: TheA Superior Sphenoidal, Maxillary. and CONNEXIONS IN THE NOSTRILS. The Frontal, (see its Connexions in the Cranium and Or- bits,]The is articulated two Nasal, in the Nostrils with seven: The Ethmoidal. TheOrbits,] Sphenoidal, is articulated (see its inConnexions the Nostrils in with the Craniumsix : and The two Palatal,Maxillary, The Ethmoidal,Vomer. and The Ethmoidal, (see its Connexions in the Cranium and Orbits,)The isFrontal, articulated in the Nostrils with eleven : The twoSphenoidal, Nasal, The two Maxillary,Lacrymal, The twoVomer. Palatal, and Theis articulatedMaxillary, in(see one its of Connexions the Nostrils in with one nineof the : Orb ItsThe Fellow, Frontal, The Sphenoidal,Ethmoidal, A Palatal,Lacrymal, AnA Nasal, inferior Spongy, and The Vomer. b xxvi BONES OF THE HEAD. Thearticulated Palatal, in(see one its of Connexions the Nostrils in with one ofsix: the Orbits,) is TheIts Fellow, Ethmoidal, AThe Maxillary, Sphenoidal, AnThe inferior Vomer. Spongy, and The Lacrymal, f see its Connexions in one of the Orbits,) is articulatedThe Ethmoidal, in one of the Nostrils with three : AAn Superior Inferior Maxillary,Spongy. The Nasal, entirely confined to the cavity of the Nose, are each Itsarticulated Fellow, in one of the Nostrils with five : The Frontal,Ethmoidal, TheA Superior Vomer. Maxillary, and Inferior Spongy, entirely confined to the cavity of the Nose, are eachA Superior articulated Maxillary, in one of the Nostrils with three : A Palatal,Lacrymal. Thewith Vomer, six: confined entirely to the Nose, is articulated The two Palatal,Superior Maxillary. The Ethmoidal,Sphenoidal. CONNEXIONS IN THE MOUTH. The Superior Maxillary, f see its Connexions in the Orbits and Nostrils,)Its Fellow, is articulated in the mouth, with ATeeth. Palatal, and Theto theInferior Mouth, Maxillary, is articulated or Lower only withJaw, confined entirely Teeth.The two Temporal, and Theis articulatedPalatal, (see in theits ConnexionsMouth, with in Orbits and Nostrils,) TheIts fellow, Superior and Maxillary. TABLE OF REFERENCE TO MitchelVs Engravings, as illustrated by Dr. Barclay. For views of the Skeleton in general, see Plates I. II. Ill FemaleFoetal Skeletons, Skeleton, PI.PI. XXIX.IV. XXXII. XXX. XXXII BONES OF THE HEAD. For Skull in general, see Plates V. VI. OsOssa Frontis Parietalia ....P I. VII. Figs. 3,1, 4.2. OssaOs Occipitis Temporum . ... PL VIII. Figs. 5,1, 6.2. Its interior and contents . Figs. 9—21.3, 6. Os EthmoidesSphenoides — — Figs. 3, 4. Ossa Unguis Figs. 31,27, 32.28. Ossa Malarum . • . . . Figs. 29,23, 30.24. Ossa MaxillariaPalati Superiora . Figs. 23, 26. OssaVomer Spongiosa Inferiora . Fig. 22.33. MaxillaTeeth Inferior ....P PI.I. IX. X BONES OF THE TRUNK. For Trunk in general, see Plates XL XII. Vertebrae PL xill. XIV. Sacrum )i PI. XV.XXL . Figs. 1, 2. Os Coccygis • >( PI. XV.XXL .. Figs. 3, 4. • >( PI. XV.XXI . Fig. 5.3. RibsOssa andInnominata Sternum . PI. XVI.XXII. XVII. BONES OF THE ATLANTAL EXTREMITIES. For ClavicleScapula ... see Plate XVIII...... Figs. 3,1, 4,2. 5. HumerusUlna P I. XIX Figs.ig. 3.1, 2. EightRadius bones of Carpus ) Fig. 4. MetacarpusThumb and fingers,. . . . >) PI. XX. BONES OF THE SACRAL EXTREMITIES. For OsTibia Femoris . . see PPlateI. XXIIIXXIV . . . . Figs. 1, 2. RotulaFibula ..... PI. XXIII...... Figs.Figs. 3,3, 4.4. Bonesnexion of the foot in con-P I. XXV. Do.Ossa separated Sesamoidea ... . . PI. XXVI. TO THE STUDENTS OF ANATOMY, UNIVERSITY OF EDINBURGH. (prefixed to the seventh edition.) GENTLEMEN, When this Osteology was first printed in 1726, I did not know that Albinus, Winslow, and Palfyn, were to publish descriptions of the bones; otherwise my papers probably would have remained yet undelivered to the printers. I however flatter myself, that this Essay has been of use to the gentlemen who did me the honour to attend my lec- tures, by assisting them to understand my sense and re- presentation of things in this fundamental part of anatomy; and that it has possibly been of more advantage to them than a more complete work from an abler hand, unless my demonstrations had been in the order and method of such an author. This view of your improvement, Gentlemen, is a pre- vailing argument with me to cause this Essay to be re- printed ; and you cannot reasonably blame me, if I like- wise acknowledge another motive for it, which more par- ticularly relates to myself. In a new edition, an author has an opportunity of making his works more correct, com- plete, and consequently acceptable to the public, who may XXX perhaps be indulgent enough to think this little treatise not altogether useless; since more reasoning on the structure and morbid phenomena of bones is to be found in it, than in the other writers, who have confined themselves almost entirely to the descriptive or proper anatomical part of the Osteology. I have here kept to the plan of the former editions, by first considering, in the order that seemed to me most na- tural and methodical, every thing which I thought neces- sary to be known concerning bones in general; and, in the second part, I have described the several bones composing the skeleton. The bones of adults are what I principally endeavour to describe, but I have added as much of the osteogenea as I think serviceable in the practice of physic and surgery. That little might be omitted of what was formerly done on this subject, I have taken all the assistance I could from books; but have never asserted any anatomical fact on their authority, without consulting nature, from which all the descriptions are made; and therefore the quotations from such books serve only to do justice to the authors, who have remarked any thing in the structure of the parts that was commonly omitted, and to initiate you in the history of anatomy, which I once proposed to make complete, so far as related to this subject: But not being able to pro- cure several books, and being sensible how many more may have never come to my knowledge, I laid aside this design, on purpose omitted many I could have inserted, and in some places I have changed an older author for a later one, who has more fully or clearly described what I treated of. Besides anatomists, I have also named several other authors to confirm my reasoning by practical cases; of which it is not to be supposed my own experience could furnish a sufficient variety. , You will readily observe, that I quote no passages with a view to criticise or condemn them. This precaution of giving no offence, is very necessary in those who are suffi- ciently conscious of their being liable to lay themselves xxxi open to just censure; and it prevents occasions of useless wrangling, in which generally both parties are losers, and the public has little advantage. In this treatise I always make use of the most common name of each part, and have put the synonymous names to be met with in books at the foot of the page, that the read- ing might be smoother, and you might consult them at your leisure to assist you in understanding different authors. The descriptions and reasoning are here blended, with- out which I always find young anatomists are soon dis- gusted with authors: Their imaginations cannot follow a long chain of descriptions, especially when they are not taught at the same time the uses which the described parts serve: Their minds must have some relaxation, by a mix- ture of reasoning, which never misses to strike the fancy agreeably, and raises a strong desire to understand the principles on which it depends. The phenomena of diseases are all deduced in this Essay from the structure of the parts, by way of corollaries and questions ; which such an anatomical work confined me to. And this method has otherwise a good effect: For, when one meets with an useful proposition, and is obliged to employ a little thought to find out its solution, the im- pression it makes is deeper, and he acquires a fondness for it, as being in part his own discovery. My pupils have frequently assured me, that they could, with very small reflection, trace out the whole reasoning from which my conclusions were drawn; I hope their successors will also think this an agreeable manner of being instructed. Those gentlemen who desired I would add the lectures which I pronounce in my colleges as a commentary upon the text, where the diseases are mentioned, will, I persuade myself, excuse me for not complying with their desire, when they consider the design of this is to be a school- book, and how great the difference is between instructing youth in private, and pretending to inform the public. Art. xxiv. vol. v. of Medical Essays and observations, pub- XXX11 lished in this place, is one of these lectures which I gave as a commentary on the paragraph (p. 9.) concerning the different kinds of caries*. In this edition, I have corrected the mistakes and ob- scure passages which I discovered in the former, and in some places I have made the descriptions more full and exact, aiming all I could to shun unnecessary minuteness on the one hand, and a blameable inaccuracy on the other: Whether I have hit that just medium, is what you and the public must now judge. I am still of opinion, that figures of the bones would at any rate have been unnecessary in a book that is intended to be illustrated and explained by the originals themselves; but w ould be much more so now, when my late ingenious friend, Mr. Cheselden, Dr. Albinus, and Mr. Suef, have published.such elegant ones. You have advantageous opportunities in this place of studying all parts of medicine, under the professors of its different branches in the University, and of seeing the prac- tice of pharmacy, surgery, and physic, with our surgeon- apothecaries, and in the Royal Infirmary, where the dis- eased poor are carefully treated. These your interests, and, I hope, your inclinations, will lead you, Gentlemen, so to improve, as that they may become the happy means of your making a considerable figure in your several stations. What- ever assistance is in my power towards such a desirable event, shall be given w'ith the greatest pleasure by Your humble servant, ALEX. MONRO. Doctor’s* This works, Commentary p. 283. is E.published in the quarto edition of the conde-|- Traitd partie. d’osteologie, traduit de 1’Anglois de M. Monro, se THE ANATOMY OF THE HUMAN BONES. PART I. OF THE BONES IN GENERAL. Bones are covered by a membrane, named on that Periosteum. account Periosteum,* which is so necessary to them, that we must examine its texture and uses, before we can understand their structure. The periosteum, as well as most other membranes, can be divided into layers of fibres. The exterior,i composed of the fibres of the muscles connected to the bones, vary in their number, size, and direction, and consequently occasion a very great difference in the thickness and strength of the periosteum of differ- ent bones, and even of the different parts of the same bone. The internal % layer is everywhere nearly of a similar structure, and has its fibres in the same di- rection with those of the bone to which they are con- tiguous. Ought not then the name periosteum to be applied, strictly speaking, only to this internal layer, to which the others are joined in an uncertain man- ner and number ? * Membrana circumossalis, omentum ossibus impositum. f$ Central,Peripheral Barcl. of Barclay. E. E. 2 OF THE BONES IN GENERAL. Some authors (a) endeavour to prove the internal layer of fibres of the periosteum to be derived from the dura mater: For, say they, since the membrane covering the skull is plainly a production or conti- nuation of the dura mater, which passes out between the sutures; and since there are muscles on the head, as well as in other parts, which might furnish a periosteum, it is needless to assign different origins to membranes which have the same texture and uses. periosteumThey add further,extends initself proof along of thisthe doctrine,ligaments that of the articulations from one bone to another ; and there- fore is continued from its origin over all the bones of the body.—While anatomists were fond of the hypo- thesis of all membranes being derived from one or other of the two that cover the brain, a dispute of this kind might be thought of consequence ; but now that the hypothesis is neglected as useless, it is needless to examine the arguments for or against it. Except where muscles, cartilages, or ligaments are inserted into the periosteum, its external surface is connected to the surrounding parts by thin cellular membranes, which can easily be stretched consider- ably, but shorten themselves whenever the stretch- ing force is removed. When these membranes are cut off or broken, they collapse into such a small space, that the surface of the periosteum seems smooth and equal. When we attempt to tear off the periosteum from bones, we see a great number of white threads pro- duced from the membrane into them; and, after a successful injection of the arteries with a red liquor, numerous-vessels are not only seen on the periosteum, (b), but most of the fibres sent from the membrane to the bone shew themselves to be vessels entering it, with the injected liquor in them; and when they are broken, by tearing off the periosteum, the surface of the bone is almost covered with red points. (S){a) Ruysch.Havers, Epist.Osteolog. 6. tab. nov. 5. disc. fig. 1.1. 2.p. epist.16. 8. tab. 9. fig. 1. i). OF THE BONES IN GENERAL. 3 The veins corresponding to these arteries are some- times to be seen in subjects that die with their ves- sels full of blood; though such numerous ramifica- tions of them; as of the arteries, can seldom be de- monstrated, because few of them naturally contain coloured liquors, and such liquors can with difficulty be injected into them. This however is sometimes done («). The great sensibility of the periosteum in the deep- i seated species of paronychia, in exostoses, nodi, tophi, and gummata, from a lues venerea, or whenever this membrane is in an inflamed state, is a sufficient proof that it is well provided with nerves, though they are | perhaps too small to be traced upon it; and therefore one cannot well determine, whether they are sent along with the arteries in the common way, or are derived from the tendinous fibres of the muscles expanded on the periosteum (b.) Vessels also pass through the periosteum to the mar- ! row ; of which more hereafter. And frequently mus- J cles, ligaments, or cartilages, pierce through the peri- osteum, to be inserted into the bones. ' theThe muscles, chief useswhen of they the contractperiosteum or are:are stretched,1. To allow to Its uses. move and slide easily upon the bones; the smooth “1 surface of this membrane preventing any ill effects of their friction upon each other. 2. To keep in due 1 order, and to support the vessels in their passage to the bones. 3. By being firmly braced on the bones, t. • totheir assist overgrowth. in setting limits4. To to strengthentheir increase, the andconjunction to check ' of the bones with their epiphyses, ligaments, and car- tilages, which are easily separated in young creatures, rJ> when this membrane is taken away. 5. To afford con- f venient origin and insertion to several muscles which It J Note(o) Sue,Traitein page 9. d’Osteologie, traduit de I’Anglois de Mr. Monro. membranes(6) See the in disputeZimmerman. about theDissert, sensibility de irritabilit.—Act. of this and of otherGot- 1 ting. vol. 2. Haller sur la nature sensible et irritable. Whytt’s §Physiolog. 26. 34. Essays, Essay II. Reimar. Dissert, de fungo articulor. B 2 4 OF THE BONES IN GENERAL. are fixed to this membrane. And, lastly, to warn us when any injury is offered to the parts it covers; which, being insensible, might otherwise be destroy- ed without our knowledge, or endeavouring to pro- cure a remedy. When the cellular substance connecting the perios- l| teum to the surrounding parts is destroyed, these parts are fixed to that membrane, and lose the sliding mo- tion they had upon it; as we see daily in issues, or any other tedious suppurations near a bone.—When the vessels which go from the periosteum to the bones are broken or eroded, a collection of liquor is made between them, which produces a sordid ulcer or rot- ten bone. This is often the case after fractures of bones, and inflammations of the periosteum, or after small- pox, measles, spotted fevers, and erysipelas.—Do not the disorders of the periosteum coming rather along with or soon after the cutaneous than other diseases, indicate some similarity of structure in the periosteum and skin ? Bones. body,The and, Bones as areall theother most parts hard where and solidlarge parts vessels of the do not enter, are generally of a white colour ; only in a living creature they are bluish, which is owing to the blood in the small vessels under their surface. The less therefore and fewer the vessels are, and the thicker and firmer the bony surface covering the ves- sels is, the bones are whiter. Hence the bones of adults are whiter than those of children; and, in both young and old, the white colour of different bones, or of the several parts of the same bone, is always in proportion to their vessels and solidities; circum- stances which ought to be regarded by surgeons, when they are to judge of the condition of bones laid bare. Intimate Bones are composed of a great many plates*, each Structure, ofsmaller which fibrils is made (a); whichup of beingfibres irregularlyor strings uniteddisposed, by and interwoven with the other larger fibres, make a reticular work. This texture is plainly seen in the (o)* Squamae,Malpigh. bractae,Anat. plant. laminae. & oper. posthum. OF THE BONES IN GENERAL. 5 bones of foetuses, which have not their parts closely compacted, and in the bones of adults which have been burnt, long exposed to the weather, or whose composition has been made loose by diseases. The chinks, which are generally made according to the direction of the larger fibres of bones that have un- dergone the action of fire, or of the weather, shew the greater strength of these than of the fibres which connect them. Numerous accurate observations of the different times in which evacuations are made from the sides or ends of similar bones, might bid fair to determine what is the proportional force of cohesion in the two sorts of fibres. The plates are said (a) to be firmly joined to each other by a great number of claviculi, or small bony processes, which, rising from the inner plates, pierce through some, and are fixed into the more external ones. Of these nails, four kinds, viz. the perpen- dicular, oblique, headed, and crooked, have been de- scribed ; but in bones fitly prepared, I could see on- ly numerous irregular processes rising out from the plates (6.) Though the exterior part of bones is composed of firm compact plates, yet they are all more or less ca- vernous internally. In some (e. g. middle thin part of the scapula and os ilium) the solid sides are brought so near, that little cavity can be seen ; and in others (middle of os humeri, femoris, &c.) the cavities are so large, that such bones are generally esteemed to be hollow or fistular. But the internal spongy tex- ture is evident in young animals; and some of it may be seen to remain in those of greatest age, when bones are cautiously opened, after they have been kept so long as to be free of the oil they contain, or after be- ing burnt. This spongy cavernous internal part of bones, is generally called their cancelli or Lattice-work, and is formed in the following manner: The plates are ( ) Gagliard. Anat. ossium, nov. invent, illustrat. cap- 1. obs. 2. (аб) Malpigh. oper. posthum. OF THE BONES IN GENERAL. firmly joined about the middle of the hone; but as they are extended towards its ends, the more inter- nal plates separate from the exterior, and stretch out their fibres towards the axis of the bone, where they are interwoven with the fibres of other plates that have been sent off in the same way. Seeing the plates are thus constantly going off, the solid sides of the bones must become thinner, and the lattice-work must be thicker and stronger towards their ends. This is evident in many of them, where the solid sides of their middle are very thick, and the cancelli are scarce- ly observable; whereas, at the ends, where their dia- meter is greatest, the solid walls or sides are not thicker than paper, and the cancelli are numerous and large enough to fill up the whole space left between the sides. The twistings and windings which these cancelli make, and the interstices which they leave, differ con- siderably in figure, number, and size; and therefore form little cells, which are as different, but communi- cate with each other. Some writers (a) minutely re- mark these different appearances of the cancelli, after they begin to separate from the plates; and from thence distinguish them into wrinkled, perforated, and net-like. The cancelli sustain the membraneous bags of the marrow which are stretched upon them, and thereby hinder these membranous parts from being torn or removed out of their proper places, in the violent mo- tions and different postures in which the bones are employed. This support which the cancelli afford the marrow, also saves its membranes and vessels, in the lower parts of the bones, from being compressed by the weight of the marrow above. The depressions between the fibres of the external plates of bones appear like so many furrows on their surface, into each of which the periosteum enters ; by which the surface of contact, consequently the cohe- sion, between it and the bone, is considerably in- to) Gagliard. Anat. ossium, cap. 1. obs. 4, 5, 6, OF THE BONES IN GENERAL. 7 creased, and a greater number of vessels is sent from it into the bone, than if it were a plain surface. Both on the ridges and furrows, numerous little pits, or orifices of canals are to be seen, by which the vessels pass to and from the bones (a). After a successful injection, the arteries can be Vessels, traced in their course from the pits to the plates and fibres; and, in sawing, cutting, or rasping the bones of living creatures, these vessels discover themselves, by the small drops of blood which then ooze out from the most solid part of the bones. But the clearest de- monstration of the intimate distribution of these small arteries, is, to observe the effect of such a tinging substance as can retain its colour, when swallowed, digested, and mixed with the blood of any living animal, and, at the same time, has particles small enough to be conveyed into the vessels of the bones ; such is rubia tinctqrum, madder root (6) : For we see the gradual advances which this tincture makes from andthe periosteum how universally into the the more distribution internal parts of the of the liquors bones; is made, the whole bony substances being tinged.— The arteries are larger near each end than at the middle of the large bones that are much moved; be- cause they not only serve the bony plates near the ends, but pass through them to the marrow.—As ani- mals advance in age, the arteries of the bones become less capacious; as is evident, 1. From the bones of adults having less blood in them than those of children. 2. From many of them becoming incapa- ble, in old age, of admiting the coloured powders used in injections, which easily pass in youth. And, 3. From the bones of old creatures being less easily tinged with madder than those of young ones.—-If authors have not mistaken, the arteries of bones have sometimes become very large (c). Structura.(а) On this E. part of the subject, see Scarpa de Penitiori Ossium num.(б) 457-Philosoph. art. 4.—Mem. Transact, de num. 1’Acad. 442. des art. Sciences. 8. num. 1739, 443. 1742.art. 2. des(c) Sciences, Diemerbroek. 1704. Anat. lib. 9. cap. 1.—Mery. Hist. del’Acad. 8 OF THE BONES IN GENERAL. We may conclude from arteries being accompanied with veins, so far as we can trace them in every other part of the body, that there are also veins in the bones ; nay, the veins of bones can sometimes be injected and Nerves. thenThe seen bones (a). of a living animal are so insensible, that they can be cut, rasped, or burnt, without put- ting the creature to pain, and the nerves distributed in their substance cannot be shewn by dissection; from which it might be inferred that they have no nerves distributed to them: But the general tenor of nature, which bestows nerves on all the other parts, should prevent our drawing such a conclusion. And if sensibility be a sure proof of nerves entering into the composition of any part, as it is generally allow- ed to be, we have sufficient evidence of nerves here in the bones; for the granulated red flesh which sprouts out from them, after an amputation of a limb, or performing the operation of the trepan, or after an exfoliation,of bones, where is exquisitely the periosteum sensible: was And, all separated,in some ulcers the patientwith a roughsuffered instrument; racking pain, nor if was the hebone free was from touched pain after the bone was perforated (6).—The reason why the nerves of rigid hard bones become insensible, is, That all nerves must have a considerable degree of flexibility at the part where objects are applied, other- wise they cannot be affected by their impressions. We see this illustrated in a very common analogous case; the growth of a new nail; when the former one has suppurated off, the thin membrane which first ap- pears, is exquisitely sensible; but gradually becomes dull in its sensation, till it can be cut or scraped, without causing pain, after it is formed into a hard nail. decay.Growth and jj. Fromj evident, what hasthat beenthere said is aof constant the vessels circulation of bones, of fluidss in every part of them ; and that there is a per- petual waste and renewal of the particles which com- pose the solid fibres of bones, as well as of other parts (ба) Sue,Nicol. trad. Massa, d’Osteolog. lib. introd. p. 9.Anat. cap. 30. OP THE BONES IN GENERAt. of the body; the addition from the fluids exceeding the waste during the growth of the bones; the re- newal and waste keeping pretty near par in adult middle age; and the waste exceeding the supply from the liquors in old age ; as is demonstrable from their weight: For each bone increases in weight, as a person approaches to maturity; continues of nearly the same weight till old age begins, and then becomes lighter.—The specific gravity of the solid sides, on the contrary, increases by age; for then they become more hard, compact, and dense. In consequence of this, the bones of old people are thinner and firmer in their sides, and have larger cavities than those of young persons. The vascular texture of bones must make them sub- Morbid ap- ject to obstructions, ecchymoses, ulcers, gangrene, and pearances most other diseases with which the softer parts are af- exPlained- fected; and therefore there may be a greater variety of caries than is commonly described (a). Hence we can account for the following appearances. Haemorrhages from fungous flesh rising out from the most solid part of a cut bone (b). The regular alternate elevation and subsiding, or apparent pulsation, frequently to be seen in some of the cells of a carious bone. Cells resembling cancelli, sometimes seem in the part of a bone, which, in a natural state, is the most solid and firm (c). A bone as a tube including another bone within it (d). On the internal surface of the solid parts of bones Canals con- there are orifices of canals which pass outwards through itainingnarrow the plates to open into other canals that are in a Ion- - gitudinal direction, from which other transverse pas- sages go out to terminate on other longitudinal canals, and this structure is continued through the whole (o)(6) EdinburghMedical Essays, Medical vol. Essays 4. art. and21. Obs. vol. 5. art. 25. (d(c) Idem,Ruysch. ibid. Thes. 8. num. 8. Thes. 10. num. 176. B 5 ]0 OF THE BONES IN GENERAL. substance of bones, both these kinds of canals be- coming smaller gradually as they approach the outer surface (a). These canals are to be seen to the best advantage in a bone burnt till it is white: When it is broken transversely, the orifices of the longitudinal canals are in view; and when we separate the plates, the transverse ones are to be observed. Here, how- ever, we are in danger of believing both these sorts of canals more numerous than they really are ; because the holes made by the processes connecting the plates of bones have the appearance of the transverse (b), and the passages for the blood vessels resemble the longitudinal canals. I do not know how we are to keep free of error about the transverse canals, but think we may distinguish between the two kinds of longitudinal ones; for the passages of the vessels are largest near the external surface of the bone, and every transverse section of them is circular; whereas the longitudinal canals are largest near the cancelli, and their transverse sections appear to me of a flat, oval fi- ofgure, the which fluids may conveying be owing them. to the Thedifferent situation momentum of the large longitudinal canals, and of the passages of the larger vessels, makes a bone appear more dense and compact in the middle of its solid sides, than towards its outer and inner surfaces, where it is spongy. We see marrow contained in the larger transverse and longitudinal canals just now described, and thence judge that it passes also into the smaller ones. The drops of oil which we discover with a microscope everywhere on the surface of a recent bone fractured transversely, and the oozing of oil through the most solid bones of a skeleton, which renders them greasy and yellow, are a confirmation of the use of these ca- nals. Of what advantage this distribution of the mar- row through the substance of bones is, will be men- tioned when the nature and use of this animal oil is inquired into. ( ) Havers, Osteolog. nov. p. 43. (ба) Morgagn. Advers. 2. aiiimad. 23. OF THE BONES IN GENERAL. 11 Most bones have one or more large oblique canals formed through their sides for the passage of the me- dullary vessels, which are to be described afterwards. Bones exposed to a strong fire in chemical vessels, are resolved, in the same manner as the other parts of animals, into phlegm, spirit, volatile salt, fetid oil, and a black caput mortuum. But the proportion of these principles varies according to the age, solidities, and other circumstances of bones. Young bones yield the largest proportion of phlegm; spongy bones afford most oil, and solid ones give most salt and black re- siduum. Though this residuum can scarcely be chang- ed by the force of fire while it is in close vessels ; yet, when it is burnt in an open fire, the tenacious oil to Avhich it owes its black colour, is forced away, and a white earth is left that has little or no fixed salt in it. This earth seems to be the proper constituent solid part of bones, and the other principles give it firmness and tenacity. For the quantity of the earth is so great, that after all the other principles are so separated from a bone, its former size and shape remain (a) ; but it is very brittle till it is moistened with water or oil, when it recovers some tenacity- The increase of the pro- portion of earth in old people’s bones, is one reason of their being more brittle than those of young people (b). Lest any imagine the salts and oils of bones, while in a natural state, to be of the same acrid kind with those obtained from them by this chemical analysis, it is to be observed, that these principles may be ex- tracted from bones in the form of a very mild jelly, by boiling them in water. Uses of The bones sustain and defend the other parts of the body. Bones.I ternal Bones are lined within, as well as covered external- Periosteum.“ (b)(a) SuchHavers, is theOsteolog. chemical nov. analysis disc. 1.of p. bones 32. by fire, as given in themodern former chemists, editions; has butsuperseded the analysis the statementsof animal substancesof the earlier by experimenters.of gelatine, animal Bones oil, areand now earthy found salts, to bewhich composed are chiefly principally phos- phatebones, and there carbonate are about of 25lime. of gelatine,In 100 parts63 of phosphateof dried human of lime, adult and 12 OP THE BONES IN GENEBAL. ly, with a membrane; which is therefore commonly called Periosteum Internum. The internal periosteum is an extremely fine mem- brane ; nay frequently it has a loose reticular texture ; and therefore is compared by some to the arachnoid coat of the spinal marrow: so that we cannot expect to divide it into layers as we can divide the external periosteum. We can however observe its processes entering into the transverse pores of the bones, where probably they are continued to form the immediate canals for the marrow distributed through the sub- stance of the bones ; and along with them vessels are sent, as from the external periosteum, into the bone (a). These processes being of a very delicate texture, the adhesion of this membrane to the bone is so small, that it separates commonly more easily from the bone than from the marrow which it contains. Wherefore, one might call it the common membrane of the marrow, rather than by the name it now has. But whether the one or the other designation ought to be given it, is not worth a dispute. From the internal* surface of the internal perios- teum, a great number of thin membranes is produced: which, passing across the cavity, unite with others of the same kind, and form so many distinct bags, which communicate with each other; and these again are subdivided into communicating vesicular cells, in which the marrow is contained. Hence it is that the marrow, when hardened, and viewed with a micro- scope, appears like a cluster of small pearls, and that the hardened marrow of bones buried long under ground, or laid some time in water, and then dried, is granulous (6). This texture is much the same with what obtains in the other cellular parts of the body, where fat is collected; only that the cells containing the marrow are smaller than those of the tunica adipo- 2 of carbonate of lime. Cartilage which contains albumen also enters(а) Winslow,into the composition Exposition ofAnat. bone. des E.Os frais, § 82, 88. (*б )Central. Ruysch, Thesaur.E. 9. num. 2. et Advers. dec. 111. obs. 9. OP THE BONES IN GENERAL. 13 sa or cellulosa elsewhere, which is probably owing to their being inclosed in the bones, where they are not so much stretched or extended as in other parts. The Marrow is the oily part of the blood, separated Marrow, by small arteries, and deposited in these cells. Its colour and consistence may therefore vary according to the state of the vessels, and their distribution on the membranes of the cells. The marrow, as well as the other fat of the body, chemically analyzed, yields, besides oil and water, a considerable proportion of an acid liquor, but no al- kali (a). This may be the reason of its being less pu- trescent than the blood or most other parts of animals (6), which is a necessary quality in a substance that is constantly exposed to a considerable degree of heat, and is more in a stagnating condition than the other liquors. Besides the arteries, which I mentioned already, p. Secerning at7. toleast be sentone arteryfrom thefor eachbones bone; to the several marrow, bones there have is Arteries, more, whose principal use is to convey and secern this oily matter. After these arteries have pierced the so- lid side of a bone, they are divided into several branch- es, which are soon distributed everywhere on the internal periosteum, and afterwards spread their branches inwards on the medullary cells, and outwards through the tables of the bone. The blood, which remains after the secretion of the marrow, is returned by proper veins, which are col- lected from the membranes into one or two large trunks, to pass out at the same holes or passages at which the artery or arteries enter. The general rule of the small vessels decreasing in their capacities as animals advance in age, to which many phenomena in the animal economy are owing, obtains here. For though the trunks of the medullary vessels enlarge as animals turn older; yet the smaller branches become smaller; as is evident from injec- (o) Grutzmaker, Dissert, de Ossium medulla. Haller Element. Physiolog.(6) Pringle, lib. Append,4. sect. 4.to Camp Diseases, exper. 47. 14 OF THE BONES IN GENERAL. tions, which cannot be made to pass so far in these vessels of adults as of children. Hence the marrow is bloody in children, oily and balmy in middle age, and thin and watery in old people. By experiments made on the marrow, when bones of living animals are opened or cut through (a), and from the racking pain with which suppurations with- in bones are frequently attended, we have sufficient sequentlyproof that havethe membranes nerves distributed here are sensible,to them. and Hip-con- pocrates (b) might therefore justly say, that a wound penetrating into the cavity of a bone may produce a delirium. The vessels of the marrow, wrapt up in one com- mon coat from the periosteum, pass through the bones by proper canals; the most considerable of which are about the middle of each bone, and are very obli- que. Sometimes these vessels continue at a little dis- tance in their passage when the canal is divided by r small bony partition or two. From the structure of the contents of the bones we may judge how these parts as well as others, may be subject to oedema, phlegmon, erysipelas, schirrhus. &c. and may thence be led to a cure of each, before the common consequence, putrefaction, takes place and frequently occasions the loss of the limb, if not of the patient. Marrow.Uses of the bonesThe ; marrowfor by enteringis of very their considerable transverse, anduse passingto tht from them into the longitudinal canals, it is commu nicated to all the plates, to soften and connect thei: fibres, whereby they are preserved from becoming toi brittle; as we see they do in burnt bones, or thosi long exposed to the air, in people labouring undei old age, syphilis or scurvy; in all which cases, the oi. is either in too little quantity, or has its natural gooc qualities changed for worse. Besides this advantage which the substance o bones has from the marrow, their articulations art ip)(a) Aphorism.Du Vemey, § Memoirs7- aph. 24. de 1’Acad. des Sciences, J7®0. OF THE BONES IN GENERAL. 15 said (a) to receive no less benefit from it: for it is thought that the marrow passes into the articular ca- i vities, through the holes which are in the bones near the large joints. And, as a proof of this, it is alleged [ that butchers, upon seeing the greater or lesser quan- tity of marrow, in the bones of cows, can tell whether they have travelled far or little before they were slaughtered. When the marrow, after having served the uses men- tioned, is re-assumed into the mass of blood, (as it is continually, in common with all other secreted liquors that have not passages formed for conveying them out l1 of the body), it corrects the too great acrimony com- 1 municated to the saline particles of our fluids by their circulation and heat; in the same manner as lixivial salts are blunted by oil in making soap. Hence, in acute diseases, the marrow, as well as the other fat of the body, is quickly wasted, but must be immediately supplied by liquors from the vessels ; seeing the cells within the bones, which have no assistance to their contraction from the pressure of the atmosphere, can- s not collapse, as the tela cellularis under the skin does, when the liquor in its cells is absorbed; the bones i; therefore are always full. Since it is the nature of all oil to become thin and Morbid ap- i rancid when exposed long to heat, and bones have expearanceslainefl much oil in their firm hard substance, we may know P - i why an ungrateful smell, and dark coloured thin ichor, ,c proceed more from corrupted bones than from other I parts of the body; and we can understand the rea- , i son of the changes of colour which bones undergo, according to their different degrees of mortification. Hence likewise we may learn the cause of a spina 5 ventosa, and of the difficulty of curing all caries of bones proceeding from an obstruction, and consequent putrefaction of the marrow; and of the quick pulse, thirst, and hectic paroxysms, so often attending these diseases. These phenomena also teach us the reason vers,(a) JoanOsteolog. de Muralto, nov. disc. Vade 3. p.Mecum 179. Anat. Exercit. 5. § 3. Ha- 16 OF THE BONES IN GENERAL. of the fatal prognosis taken from black fetid urine in fevers. Bones.Varieties of annexedThough parts, bones yetso farwe agreemay observein their astructure considerable and difference among them in their magnitude, figure, situation, substance, connexion, uses, &c. From which authors have taken occasion to distinguish them into as many classes as they could enumerate of these different circumstances. But these being obvious to every person that looks on bones, I shall mention only one of then:; which comprehends very nearly all the bones of the body; and at the same time leads us to examine the most considerable varie- ty that is to be found in the disposition of their con- stituent parts, and in their uses. It is this, that some bones are broad and flat, while others are long and round. Bones.Broad i gThe soon broad and equally bones have sent thinoff to sides, form theby thelattice-work plates be- whichn therefore is thicker, and nearly of an equa' form all through. By this structure, they are weL adapted to their uses, of affording a sufficiently largt surface for the muscles to rise from, and move upon and of defending sufficiently the parts which the\ inclose. Bones.Round middle,The mindand becomebones havevery thickthin strongtowards walls their in ends th« which is owing to very few plates separating at thei middle; where, on that account, the cancelli are si fine and small that they are not taken notice of; bu such bones are said to have a large reservoir of oil ii this place. Towards their ends the lattice-work be comes very thick, and rather more complete than ii f, the other sort of bones.—These round bones havin - strong forces naturally applied to them, and bein ofAdvantages this otherwisecylindrical exposedfigure to to resist violent external injuries, pressure, have need and of .> form' considerable quantity of oil to preserve them from be coming too brittle. Besides which, they are advan tageously provided with thick sides towards thei middle, where the greatest forces are applied to ir OF THE BONES IN GENERAL. 17 jure them ; while their hollowness increases their dia- j meter, and consequently, their strength to resist forces i applied to break them transversely (a). Thus, for in- stance, in estimating the proportional resistance of two cylindrical bones of unequal diameters, but con- sisting of an equal number of similar fibres uniformly disposed round each, it is plain, 1. That the abso- lute force of these two bones is equal, because they !1 consist of equal numbers of similar fibres. 2. That the absolute forces of all the fibres in each bone have the same effect in resisting any power applied to break them, as if the sum of all their forces were united in i the respective centres of the transverse sections where the fractures1 are to be made. Tor, by hypothesis, the fibres eing uniformly disposed in each, there is I! not any fibre in either bone that has not a correspond- ing fibre; the sum of both whose distances from the axis of revolution (about which all the parts of the ' bone must revolve in breaking) is equal to two semi- alldiameters the fibres, of themay bone:be regarded consequently as resisting each at fibre, the dis-and , tance of one semi-diameter or radius from this axis, that is, in the centre. 3. Since the united force of all ,, the fibres is to be regarded as resisting at a distance from the centre of motion equal to the semi-diameter, i it follows, that the total resistance of all these fibres, \ or the strength of the bone, is proportional to its semi- diameter, and consequently to its diameter. I have here taken for an example, one of the tnost i simple cases for calculating the proportional forces of ! bones. But, were it not foreign to the present design, , it might be universally demonstrated, that, of whatever figure bones are, and in whatever manner their fibres . are disposed, their strength must always be in a ratio compounded of the area of their transverse sections, I or of their quantity of bony matter, and of the dis- : tance of the centre of gravity of these sections from the centre of motion or fulcrum, on which the bone . is supposed to be broken (6). (a) Galilei, Mechanic, dialog. 2. : i: in (6)the See Edinburgh the demonstration Medical Essays, of this vol. theorem i. art. by10. Dr. Porterfield, 18 OP THE BONES IN GENERAL. Since therefore the strength of bones depends on their number of fibres or quantity of matter, and the largeness of their diameters, we may conclude, that the part of a bone formerly fractured, and re-united by a callus, must be stronger than it was before the fracture happened; because both these advantagesIJ are obtained by a callus ; which is a wise provision, since bones are never set in such a good direction as they were naturally of; and then wherever a callus is formed, there is such an obstruction of the vessels, that if the bone were again broken in the same place, the ossific matter could not so easily be conveyed to re-unite it. This callus may indeed, for want of compression, be allowed to form into a spongy cellu- lar substance (a); but even in this case, the strength of the bone is here increased by one or both causes Processes. aboveMany mentioned. bones have protuberances, or processes,* rising out from them. If a process stands out in a roundish ball, it is called caput, or head.—If the head is flatted, it obtains the appellation of condyle.A rough unequal protuberance, is called tuberosity.— When a process rises narrow, and then becomes large the narrow or small part is named cervix, or neck.— Long ridges of bones are called spines.—Such pro- cesses as terminate in a sharp point, have the genera' name of coronie,f or coronoid, bestowed on them though most of them receive particular names fron the resemblance they have, or are imagined to have, t« other substances, e. g. mastoid, styloid, anchoroid, co racoid, spinal, fyc. Such processes as form brim of cavities, are called supercilia.% Processes serve for the advantageous origin am (a) Ruysch. Thesaur. 8. n. 49. Mus. Anat. theo. B. reposit 2. *n. 'Aviifumis2. txfvrtts OP THE BONES IN GENERAL. 33” head or cavity, or where they are joined by plain surfaces, or nearly so ; such is the conjunction of the clavicle with the scapula ; ossa cuneiformia with the os naviculare ; metatarsal bones with the ossa cunei- formia, &c. From the nature of this sort of joint, it is plain, that very great motion cannot be allowed, without the bones going farther out of their natural situation, than is convenient or safe. Ginglimus, I would reckon that articulation by the form of which the motion of the joined bones, must be chiefly confined to two directions, as hinges of doors are. i The first species of this is the trochoides, when one I bone turns on another, as a wheel does on its axis; Thus the first vertebra of the neck moves on the tooth- like process of the second. This is the most proper kind of ginglimus. ■ The second species should be esteemed that articu- . lation where several prominent and hollow surfaces of two bones move on each other, within the same com- . mon ligament; as in the knee, elbow, &c. The third sort of ginglimus is, when two bones are articulated to each other at different parts, with a dis- tinct apparatus of the motory machines at each; such ,, is the articulation of the os occipitis with the first ver- tebra of the neck; of any two contiguous vertebras, by their oblique processes; of the ribs with the bo- dies and transverse processes of the vertebrcc; of the radius with the ulna, tibia with \)iq fibula, astragalus u with the calcaneum, &c. I would entirely throw out what is commonly . called the third kind of ginglimus : For, in examin- , ing the conjunction of a bone with two others, as in the common example of a vertebra joined with the one above and below, the connection of the middle one with each of the other two ought to be considered se- . parately; otherwise we might with the same proprie- tv esteem the articulations that the long bones, the Temur, tibia, humerus, &c. have at their different ends, as one articulation; which is absurd. If the moveable bones are not connected and kept firm by some strong substance, they would be luxated c 5 34 OP THE BONES IN GENERAL. at every motion of the joints : and if their hard rough unequal surfaces were to play on each other, theii motion would not only be difficult, but the loss of sub- stance from attrition would be great. Therefore liga- ments are made to obviate the first, and cartilages tc prevent the other inconveniency. But because liga- ments and cartilages turn rigid, inflexible, and rough unless they are kept moist, a sufficient quantity o: proper liquors is supplied for their lubrication, and tc preserve them in a flexible state. Seeing then thes« parts are so necessary to the articulations, I shall nex’ consider their structure, situation, and uses, so far as they are subservient to the bones, and their motions. Ligaments. firmerLigaments than membranes, * are white and flexible not sobodies, hard thickeror firm anc a: cartilages, without any remarkable cavity in their sub stance, not easily stretched, and with little elasticity serving to connect one part to another, or to preven the parts to which they are fixed from being removec out of that situation which is useful and safe. After maceration in water, the ligaments can easib be divided ; and each ligamentous layer appears com posed of fibres, the largest of which are disposed in : longitudinal direction. The arteries of ligaments are very conspicuous afte a tolerable injection, and the larger trunks of the! veins are sometimes to be seen full of blood. Such ligaments as form the sides of cavities, hav> numerous orifices of their arteries opening upon thei internal surface, which keep it always moist: If w> rub oflF that moisture, and then press the ligaments we can see the liquor oozing out from small pores and we can force thin liquors injected by the arterie into the cavities formed by ligaments. These exhalant arteries must have correspondinj absorbents, otherwise the cavities would soon be to* full of liquor. Ligaments then must be subject to the diseases com- mon to other parts, where there is a circulation oi fluids, allowance being always made for the size of * Xutht/ui, iwgM, copula, vincula. OF THE BONES IN GENERAL. 35 vessels, nature of the fluids, and firmness of the tex- ture of each part. Authors generally say, that ligaments are insensi- ble ; and consequently it may be inferred, that they have no nerves bestowed on them. But the violent racking pain felt on the least motion of a joint labour- ing under rheumatism, the seat of which disease seems often to be in the ligaments, and the insufferable tor- ture occasioned by incisions of ligaments, and by a collection of acrid matter in a joint, or by tophi in the gout, would persuade us, that they are abundantly supplied with nerves. The ligaments which connect the moveable bones commonly rise from the conjunction of the epiphyses of the one bone, and are inserted into the same place of the other; or where epiphyses are not, they come out from the cervix, and beyond the supercilia of the articulated bones ; and after such a manner, in both cases, as to include the articulation in a purse or bag, with this difference, depending on their different mo- tions, that where the motion is only to be in two di- rections, the ligaments are strongest on those sides towards which the bones are not moved; and when a great variety of motions is designed to be allowed, the ligaments are weaker than in the former sort of articulations, and are nearly of the same strength all round. Part of the capsular ligaments is composed of the periosteum, continued from one bone to another, as was observed, p. 2, and their internal layer is conti- nued on the parts of the bone or cartilage which the ligament includes (a). Besides these common capsular ligaments of the joints, there are particular ones in several places, ei- ther for the firmer connection of the articulated bones, or for restraining and confining the motion to some one side; such are the cross and lateral ligaments of the knee, the round one of the thigh, &c. From this account of the ligaments, we may con- (a) Nesbit, Osteogen.—Philos, transact. No. 470. § 6. c 6 36 OF THE BONES IN GENERAL. elude, that, cceteris paribus, in whatever articulation the ligaments are few, long, and weak, the motion is more free and quick; but luxations happen frequently ; And, on the contrary, where the ligaments are numer- ous, short, and strong, the motion is more confined; but such a joint is less exposed to luxations (a). Whence we may judge how necessary it is to attend to the different ligaments, and the changes which have been made on them by a luxation, when it is to be re- Their uses. duced.Ligaments also supply the place of bones in several cases to advantage: Thus the parts in the pelvis are more safely supported below by ligaments, than they could have been by bones.- The ligaments placed in the great holes of the ossa innominata, and between the bones of the fore-arm and leg, afford convenient origin to muscles Immoveable bones are firmly connected by them; of which the conjunction of the os sacrum and innominatum is an example They afford a socket for moveable bones to play in, as we see part of the astragalus does on the ligament stretchy ed from the heel-bone to the scaphoid. Numerous inconveniences may arise from too long or short, strong or weak, lax or rigid ligaments (6). Cartilages. Cartilages* are solid, smooth, white, elastic sub- stances, between the hardness of bones and of liga- ments, and covered with a membrane namedperichon~ drium, which is of the same structure and use to them as the periosteum is to the bones. Cartilages are composed of plates, which are formed! of fibres, disposed much in the same way as those of bones; as might be reasonably concluded from ob- serving bones in a cartilaginous state before they ossi- fy, and from seeing, on the other hand, so many carti- lages become bony. This may be still farther confirm- ed, by the exfoliation to which cartilages are subject, as well as bones. (а) Fabric, ab Aquapend. de articul. part, utilit. pars. 3. chat,(б) Anat.On the Gener. ligaments, T. in. see andWeichtbrecht’s Anat. Descrip. Syndesmologia, T. 1. and Cal-Bi- dani’s* splendid collection of Anatomical Engravings. E. OP THE BONES IN GENERAL. 37 The perichondrium of several cartilages; for exam- ple, those of the ribs, and larynx, has arteries which can be equally well injected with those of the perios- teum ; but the vessels of that membrane in other parts, e. g. the articular cartilages, are smaller, and in none of them does injection enter deep into the substance of , animals,the cartilages; does not nay, change madder the colourmixed of with cartilages, the food as ofit i does that of bones (a). The granulated flesh which arises from the ends of metacarpal or metatarsal bones, when the cartilage ex- foliates after a finger or toe has been taken off at the first joint, is very sensible, from which the existence j of nerves in cartilages may be inferred. While cartilages are in a natural state, it is to be re- marked, 1. That they have no cavity in their middle for marrow. 2. That their outer surface is softest, , which renders them more flexible. 3. That they do not appear to change their texture nearly so much by acids as bones do; and, last, That as the specific gra- ? vity of cartilages is nearly a third less than that of bones, so the cohesion of their several plates is not so t strongwounds asor inulcers, bones; are whencenot only cartilagesmore liable laid to corrupt,bare in i but exfoliate much sooner than bones do. ; Cartilages seem to be principally kept from ossify- » ing, either by being subjected to alternate motions of flexion and extension, the effects of which are very different from any kind of simple pressurey or by be- ,»f ingthe constantlyarticulated moistenedends of the (6): great Thus, bones the ofcartilages the limbs, on m and the moveable ones placed between the moving bones in some articulations, which are obliged to suffer many and different flexions and are plentifully moist- ened, scarcely ever change into bone ; while those of the ribs and larynx are often ossified—The middle angular part of the cartilages of the ribs, which is con- stantly in an alternate state of flexion and extension, (a) Philos. Transact. No. 442. art. 8. No. 443. art. 2. No. 457- ossiumart. 4, Mem.callo. de I’acad. des sciences(5) 1739Havers, et 1742—DehtleefOsteolog. nov. de 38 OF THE BONES IN GENERAL. by being moved in respiration, is always the last to become bony.—In the larynx, the epiglottis, which is oftener bended and more moistened than the other four cartilages, is seldom ossified, while the others as seldom escape it in adults. The cartilages subservient to bones, are sometimes found on the ends of bones which are joined to no other; but are never wanting on the ends, and in the cavities of such bones as are designed for motion (a). Cartilages also are interposed between such other car- tilages as cover the heads and cavities of articulated bones; nay, they are also placed between immove- able bones. Their uses. The uses of cartilages, so far as they regard bones, are, to allow, by their smoothness, such bones as are designed for motion, to slide easily without detrition, while, by their flexibility, they accommodate them- selves to the several figures necessary in different mo- tions, and, by their elasticity, they recover their natu- ral position and shape as soon as the pressure is re- moved—This springy force may also render the mo- tion of the joint more expeditious, and may diminish shocks in running, jumping, &c. To these cartilages chiefly we owe the security of the moveable articula- tions : For without them the bony fibres would sprout out, and intimately coalesce with the adjoining bone; whence a true anchylosis must necessarily follow; which never fails to happen when the cartilages are eroded by acrid matter, or ossified from want of mo- tion or defect of liquor, as we see often happens after wounds of the joints, paidarthrocace, scrophula, and spina ventosa, or from old age, and long immobility of joints (6).—Hence we may know what the annihi- lation is which is said to be made of the head of a bone, and of the cavity for lodging it, after an unreduced fracture (c). The moveable cartilages interposed in (a) Cels, de re medic, lib. 8. cap. 1. sciences(J) Columb. 1716 dePhil, re anat. transact. lib. 15.No. Deslandes, 215. Ibid. Hist, No. del’acad. 461. § 16. des Thes.(c) Hildan.8. No. 103. de ichor,Saltzman et melicer. in act. acriPetropolit. Celsi, tom.cap. 5.3. Ruysch.p. 275. OF THE BONES IN GENERAL. joints, serve to make the motions both freer and more safe than they would otherwise be -Those placed on the ends of bones that are not articulated, as on the spine of the os i/mm, base of the scapula, &c. serve to prevent the bony fibres from growing out too far Cartilages sometimes serve as ligaments, either to fasten together bones that are immoveably joined ; such are the cartilages between the os sacrum and ! ossa ilium, the ossa pubis, &c. or to connect bones that enjoy manifest motion, as those which are placed between the bodies of the true vertebrae, &c. Carti- lages very often do the office of bones to greater ad- | vantage than these last could, as in the cartilages of , the ribs, those which supply brims to cavities, &c. Too great thickness or thinness, length or shortness, : hardness or suppleness of cartilages, may therefore • cause great disorders in the body. The liquor, which principally serves to moisten the aSynovialaratus 5 ligaments and cartilages of the articulations, is sup- PP - 't plied by glands, which are commonly situated in the » joint, after such a manner as to be gently pressed, but i not destroyed by its motion. By this means, when t, there is the greatest necessity for this liquor, that is, i, when the most frequent motions are performed, the c greatest quantity of it must be separated. These glands t: are soft and pappy, but not friable. In some of the ,c large joints, they are of the conglomerate kind, or a si great number of small glandules are wrapt up in one common membrane. Their excretory ducts are long, m and hang loose, like so many fringes, within the arti- i( culation; which, by its motion and pressure, prevents ;w obstructions in the body of the gland or its excretories, ,i i and promotes the return of this liquor, when fit to be 4 taken up by the absorbent vessels, which must be in .U the joints, as well as in the other cavities of the body; i and, at the same time, the pressure on the excretory ducts hinders a superfluous unnecessary secretion, while the fimbriated disposition of these excretories H does not allow any of the secreted liquor to be pushed back again by these canals towards the glands (a). («) Cowper, Anatom, explicat. tab. 79. lit. 40 OP THE BONES IN GENERAL. Very often these fountains of slimy liquor appear onlyalmost as concealeda network by of cellularvessels.—Frequently membranes containing they are the fat—and sometimes small simple mucous folliculi may be seen, (a) The different joints have these organs in different numbers and sizes ; the conglomerate ones do not vary much, especially as to situation, in the similar joints of different bodies; but the othefs are more uncertain. Synovia. weUpon can squeeze pressing out any of oftheir these excretories glands with a mucilaginous the finger, liquor, which somewhat resembles the white of an egg, or serum of the blood ; but it is manifestly salt to the taste. It does not coagulate by acids or by heat, as the serum, but by the latter turns first thinner, and, when evaporated, leaves only a thin salt film. The quantity of this mucilage, constantly supplied, must be very considerable, since we see what a plen- tiful troublesome discharge of glairy matter follows a wound or ulcer of anv joint; of which liquor the mu- cilage is a considerable part. The vessels which supply liquors for making the secretion of this mucilage, and the veins which bring back the blood remaining after the secretion, are to be seen without any preparation ; and, after a tolerable injection of the arteries, the glands are covered with them. In a sound state, we are not conscious of any sen- sibility in those glands; but in some cases which I have seen, when they inflame and suppurate, the most racking pain is felt in them ;—a melancholy, though sure proof that they have nerves. These mucilaginous glands are commonly lodged in cellular substance; which is also to be observed in other parts of the bag formed by the ligaments of the articulation ; and contains a fatty matter, that must necessarily be attenuated, and forced through the in- cluding membranes into the cavity of the joint, by the pressure which it suffers from the moving bones. (a) Morgagn. Adversar. 2, animad. 23. OP THE BONES IN GENERAL. 41 If then the oil is conveyed from this cellular sub- stance ; and if the attenuated marrow passes from the cancelli of the bones by the large pores near their ends, or in their cavities, and sweats through the car- tilages there into the articulations; which it may, when assisted by the constant heat and action of the body, more easily do, than when it escapes through the compact substance of the bones in a skeleton: If, I say, this oil is sent to a joint, and is incorporated with the mucilage, and with the fine lymph that is constantly oozing out at the extremities of the small arteries distributed to the ligaments, one of the fittest liniments imaginable must be produced; for the mucus diluted by the lymph contributes greatly to its lubri- pity, and the oil preserves it from hardening. How well such a mixture serves the purpose it is designed for, Boyle (a) tells us he experienced in working his air-pump ; for the sucker could be moved with much less force, after being moistened with water and oil, ;han when he used either one or other of these li- i juors. And I believe every one, at first view, will al- ow the diluted mucilage to be much preferable to r ample water. The synovia * as this liquor, composed af oil, mucilage, and lymph, is commonly now called, i> vhile in a sound state, effectually preserves all the f* jarts concerned in the articulations soft and flexible, i tnd makes them slide easily on each other, by which i heir mutual detrition and over-heating is prevented, a the manner daily practised in coach and cart i*: 1 riieels,After bythe besmearing liquor of themthe articulationswith grease andbecomes tar. too i9 bin and unserviceable, by being constantly rubbed etween the moving bones, it is re-assumed into the s lass of blood by the absorbent vessels. ; 3 When the synovia is not rubbed betwixt the bones, ti ; inspissates. And sometimes, when the head of a .1 one has been long out of its cavity, this liquor is said > :• d fill up the place of the bone, and hinder its reduc-. (a)* Physico-mechanic.mucus, axungia. experim. 42 OP THE BONES IN GENERAL. tion; or if a joint continues long unmoved, it is als« said to cement the bones, and occasion a true anchy- losis (a.) If the synovia becomes too acrid, il erodes the cartilages and bones ; as frequently hap- pens to those who labour under the lues venerea, scur- vy, scrofula, or spina ventosa.—li this liquor is se- parated in too small quantity, the joint becomes stiff and when it is moved with difficulty, a crackling noisi is heard, as people advanced in years frequently ex perience (6).—If the mucilage and lymph are depo sited in too great quantity, and the absorbent vessel do not perform their office sufficiently, they may oc casion a dropsy of the joints (c).—From this sam cause also the ligaments are often so much relaxed as to make the conjunction of the bones very weak Thence arise the luxations from an internal cause which are easily reduced, but not easily cured (d).— —-Frequently, when such a superfluous quantity c this liquor is pent up, it becomes very acrid, and oc casions a great train of bad symptoms ; such as swell ing and pain of the joints, long sinuous ulcers an Jistula, rotten bones, immobility of the joints, marco and atrophia of the whole body, hectic fevers, &c. (e).- From a depravity in the blood, or diseases in the 01 gans that furnish the synovia of the joints, it may t greatly changed from its natural state ; it may be pc rulent after inflammation, mucous in the white swel lings, gelatinous in the rheumatism, chalky from tl. gout, &c.; hence a great variety of disorders in th|; joints (fj. (a) Pare, Chirurgie, livre 15. chap. 18. et livre 16. cap. 5. Aquapend.(5) Galen, de de articul. usu part. part, lib. utilitat. 12. cap.pars 23. Fabric,-Bartholii l Hist,(c) medic,Hildan. cent. de ichore 3. hist. et 11.meliceria acri Celsi. (d)(e) Hippocrat.Hildan. de deichore locis et in meliceria homine, acri§ 14. Celsi. et de articul. On(f) theSee synovialReimar, apparatus,Disser. de see fungo Munro articulor. on the Bursae Mucosa and Bichat, Anat. Gener. T. 4. £. ANATOMY OF THE HUMAN BONES. PART II. OF THE SKELETON. Though any dry substance may be called skeleton, De&mtioju yet, among anatomists, this word is universally un- derstood to signify the bones of animals connected to- gether, after the teguments, muscles, bowels, glands, nerves, and vessels are taken away.* A skeleton is said to be natural, when the bones Natural1 are kept together by their own ligaments ; and it isC an*la1, Artifi- called artificial, when the bones are joined with wire, or any other substance which is not part of the crea- ture to which they belonged. Small subjects, and . such whose bones are not fully ossified, are commonly ' prepared the first way; because, were all their parts * livided, the nicest artist could not rejoin them, by ' reason of their smallness, and of the separation of ;heir unossified parts; whereas the bones of large idultid when animals single, are and soonest are andeasily most restored conveniently to, and clean- kept ji their natural situation.—Sometimes the skeletdn of he same animal is prepared in both these ways ; that s, the smaller bones are kept together by their natu- al ligaments, and the larger are connected by wires, •r some such substances. Before we proceed to the division and particular Relative si- nark,lescription that whenof the the skeleton, bones are it put is worthinto their while natural to re- ttuationhe Bones. of Cadaveris crates. 44 OF THE SKELETON. situation, scarcely any one of them is placed in a per- pendicular bearing to another; though the fabric com- posed of them is so contrived, that, in an erect pos- ture, a perpendicular line, from their common centre of gravity, falls in the middle of their common base (a). On this account, we can support ourselves as firmly as if the axis of all the bones had been a straight line perpendicular to the horizon; and we have much greater quickness, ease, and strength in several of the most necessary motions we perform. It is true indeed, that wherever the bones, on which any part of our body is sustained, decline from a straight line, the force required in the muscles, to counteract the gravity of that part, is greater than otherwise it needed to have been; but then this is effectually provided for in such places, by the number and strength of the muscles. So long therefore as we remain in the same posture, a considerable number of muscles must be in a constant state of contraction; which we know, both from reason and experience, must soon create an uneasy sensation,. This we call, being weary of one posture, an incon- venience that we should not have had in standing erect, if the bearing of all the bones to each other had been perpendicular; but is more than compen- sated by the advantages above mentioned. The human skeleton is generally divided into the Head, the Trunk, the Superior, and the Inferior Extremities. of the head. By the Head is meant all that spheroidal part which is placed above the first bone of the neck. It there- fore comprehends the cranium and bones of tlaeface. | Cranium. veralThe pieces, cranium,* which helmet, form a or vaulted brain-case, cavity, consists for lodging of se-l, and defending the brain and cerebellum, with theii membranes, vessels, and nerves. (a) Cowper, Anat. of Human Bodies, explic. of tab. 39. theca* Koyxof, et olla capitis,xvth, »uiwt, testa capitis,tTKaipjai, scutella calva, calvaria,capitis. cerebri' gafea,' , OF THE SKELETON. 45 The cavity of the cranium is proportioned to its contents. Hence such a variety of its size is observed in different subjects; and hence it is neither so broad nor so deep at its fore-part, in which the anterior lobes of the brain are lodged, as it is behind, where the large posterior lobes of the brain, and the whole cerebellum, are contained. The roundish figure of the skull, which makes it Figure, more capacious, and better able to defend its contents from external injuries, is owing chiefly to the equal pressure of these contained parts as they grow and increase before it is entirely ossified.——It is to be observed, however, that the sides of the cranium are i depressed below a spherical surface by the strong i temporal muscles, whose action hinders here the uni- form protrusion of the bones, which is more equally performed in other parts, where no such large mus- |; cles are. In children, whose muscles have not acted much, and consequently have not had great effects on t the bones, this depression is not so remarkable; and it therefore their heads are much rounder than in adults, s These natural causes, differently disposed in diflerent e people, produce a great variety in the shapes of skulls, j which is stfll increased by the different management of the heads of children when very young, So that is one may know a Turk's skull by its globular figure, a id German's by its breadth and flatness of the occiput, Dutch and English by their oblong shapes, &c. (a). Two advantages are reaped from this flatness of the sides of the cranium, viz. the enlargement of our sphere of vision, and more advantageous situation of our ears i for receiving a greater quantity of sound, and for be- ,3i ing less exposed to injuries. The external surface of the upper * part of the era- Surfaces, i* nium is very smooth and equal, being covered only ; with the periosteum, (common to all the bones; but in ’» the skull, distinguished by the name oipericranium,) ,, (a) Vesal. lib. 1. c. 5. See algo Blumenbach, Collect. Cran. f.'*!lr idivers.* Peripheral gent. surfacesE. of the coronal, glabellar, and inial parts. E. 46 OF THK SKELETON. theaponeurotis, thin frontal and and with occipital the common muscles, teguments their tendinous of the body; while the external surface of its lower* part has numerous risings, depressions, and holes, which afford convenient origin and insertion to the muscles that are connected to it, and allow safe passage for the vessels and nerves that run through and near it. The internalf surface of the upper part of the skull is commonly smooth, except where the vessels of the dura mater have made furrows in it, while the bones were soft.- - Surgeons should be cautious when they trepan here,■ lest, in sawing or raising the bone Where such furrows are, they wound these vessels ——In the upper part of the internal surface of seve- ral skulls, there are likewise pits of different magni- tudes and figures, which seem to be formed by some parts of the brain being more luxuriant and prominen! than others. Where these pits are, the skull is so mud. thinner than anywhere else, that it is often renderec diaphanous, the two tables being closely compactec without a diploe; the want of which is supplied bj vessels going from the dura mater into a great man] small holes observable in the pits. These vessels are larger, and much more conspicuous than any others that are sent from the dura mater to the skull; as evi- dently appears from the drops of blood they pour out when the skull is raised from the dura mater in a re- cent subject; and therefore they may furnish a suffi- cient quantity of liquors necessary to prevent the brit- tleness of this thin part—The knowledge of these piti should teach surgeons to saw cautiously and slowlj through the external table of the skull, when they ar« performing the operation of the trepan; since, in a pa tient whose cranium has these pits, the dura mater ant brain may be injured, before the instrument has pier- ced near the ordinary thickness of a table of the skull —The internal base of the skull is extremely unequal for lodging the several parts and appendices of thi brain and cerebellum, and allowing passage and de- Basilar part. E. •f Central surface. E. OIF THE SKELETON. 47 fence to the vessels and nerves that go into, or come out from these parts. The bones of the cranium are composed of two ta- Tables and hies, and intermediate cancelli, commonly called their Diploe. | diploe*. The external table is thickest; the inner, from its thinness and consequent brittleness, has got the name of vitrea. Whence we may see the reason of those mischievous consequences which so often at- tend a collection of matter in the diploe, from either an external or internal cause, before any sign of such a collection appears in the teguments that cover the part of the skull where it is lodged (a). The diplo'e has much the same texture and uses in | the skull, as the cancelli have in other bones The diplo'e of several old subjects is so obliterated, that scarcely any vestige of it can be seen ; neither is i it observable in some of the hard craggy bones at the base of the skull. Hence a useful caution to surgeons who trust to the bleeding, want of resistance, and change of sound, as certain marks in the operation of the trepan, for knowing when their instrument has sawed through the first table, and reached t\iediplo'e{b). In other people, the rfip/oe becomes of a monstrous thick- ness, whilethe tables of theskull arethinnerthan paper. The cranium consists of eight bones, six of which Component are said to be proper, and the other two are reckoned bones, common to it and to the face.—The six proper are the osfrontis, two ossa parietalia, two ossa temporum, and the os occipitis.—The common are the os ethmoides and sphenoides. The os frontis forms the whole fore f part of the vault; the two ossa parietalia form the upper and mid- ' die £ part of it; the ossa temporum compose the lower part of the sides; the os occipitis makes the whole hinder part, and some of the base; the os ethmoides is placed in the fore part of the base, and the os sphe- - noides is in the middle of it. * Meditullium, commissura. !i (o)(6) Bonet.Bartholin. Sepulchret. Anat. reform, Anat. lib.lib. 4.1. cap.§ 1. 4.obs. 96.—103. tJ Glabellar.Coronal and E. mesial. E. ' 48 OF THE SKELETON. Sutures. tures;These the bones names are of joined which toare eachthe coronal,other by lambdoic, five su sagittal, ajid two squamous. Coronal. fromThe within coronal* an inch suture or so is of extended the external over t canthusthe head c one eye, to the like distance from the other; whic being near the place where the ancients wore thei xnttce, coronce, or garlands, this suture has hence go its name.—Though the indentations of this suture ar conspicuous in its upper part, yet an inch or more c its end on each side has none of them ; for it is squa mous and smooth there. dal.Lambdoi- andThe farther lambdoidal back than J suture the vortex begins or crownsome ofway the below head whence its two legs are stretched obliquely down ' wards, and to each side, in form of the Greek letter A and are now generally said to extend themselves t the base of the skull; but formerly anatomists (a reckoned the proper lambdoid suture to terminate a the squamous sutures, and what is extended at an angL down from that on each side, where the indentation are less conspicuous than in the upper part of the su ture, they called additamentum suturae lambdoidis []. This suture is sometimes very irregular, being madi up of a great many small sutures, which surround s> many little bones that are generally larger and mon conspicuous on the external surface of the skull, thai internally. These bones are generally called trique tra or Wormiana ; but some other name ought to hi given them, for they are not always of a triangular fi- gure; and older anatomists (6) than Olaus Wormius (c have described them.—The specific virtue which thesi bones were once thought to have in the cure of th« f* Lateral.’Srsfataiic, E. arcualis, puppis. (a)j Lauda-, Vesal, proAnal.™, hypsyloides.lib. 1. cap. 6'. (4)|| Lambdoidesharmonialis,lambdoides Eustacb. Ossium examen.—Bauhin. inferior, Theat. occipitiscorona. Anat. lib. 8. cap.(c.) 5. Musseum, Paaw, lib. in3. Hippocrat.cap. 26. de vulner. cap. p. 56. OF THE SKELETON. 49 epilepsy (a) is not now ascribed to them; and ana- tomists generally agree, that their formation is owing to a greater number of points than ordinary of ossifica- tion in the skull, or to the ordinary, bones of the cra- nium not extending their ossification far enough or soon enough ; in which case, the unossified interstice between such bones begins a separate ossification in one or more points : from which the ossification is ex- tended to form as many distinct bones as there were points that are indented into the large ordinary bones, and into each other.—Probably those children who have a large opening in this place at their birth, will have the largest ossa Iriquetra—To confirm this ac- count of the formation of these little bones, we may remark, that such bones are sometimes seen in other sutures, as well as in the lambdoid (b), and they are kometimes in one table of the skull, and not in the >ther (c). j The sagittal suture * is placed longitudinally, in Sagittal. • he middle of the upper part of the skull, and com- nonly terminates at the middle of the coronal, and of he lambdoid sutures; between which it is said to be daced, as an arrow is between the string and bow.— ' lowever, this suture is frequently continued through he middle of the os frontis, down to the root of the ose; which, some {d) say, oftener happens in wo- “ ten than men; but others (e) allege, that it is to be ‘ let with more frequently in male skulls than in fe- • lale: Among the skulls which I have seen thus di- ided, the female are the most numerous.—Several a (a) Bauhin. et Paaw, ibid.—Bartholin. Anat. reform, lib. 4. > ip.(6) 5.—Hildan. See examples Epistol. in VesaL 65. lib. 1. cap. 6. fig, 4 Paaw in 1.ippocrat. Ruysch. de Mas. cap. Anat.—Sue,vuln Bartholin. Trad, Hist.d’osteolog. Anat. pccent. 47. 1. hist. (c)* 'PaCiouint,Hunauld. ina&sXata, Mem. devri^iwytura, I’acad. des instarsciences, virgae, 1730. nervalis, : tns,star conjungens,teli, instar veru,columnalis, secundum recta, capuis, acualis. longitudinem prore- (d)(e) Riolan.Vesal, lib.Comment, 1. cap. 6.de etossib. in epitome. cap. 8. 50 OF THE SKELETON. (a) have delineated and described the sagittal suturi sometimes dividing the occipital bone as far down £ the great hole through which the medulla spinali passes. This I never saw. In some old skulls that are in my possession, the] is scarcely a vestige of any of the three sutures whic I have now described. In other heads, one or two the sutures only disappear; but I never could disc' ver any reason for thinking them disposed in such di ferent manners in skulls of different shapes, as son ancients allege they are (b). Squamous. The squamous, agglutinations, or false sutures*, a one on each side, a little above the ear, of a semici cular figure, formed by the overlapping (like o: scale upon another) of the upper part of the tempor bones on the lower part of the parietal, where, in bo bones, there are a great many small risings and ft rows, which are indented into each other; thou; these inequalities do not appear till the bones are s parated. In some skulls indeed, the indentations he are as conspicuous externally as in other sutures (c and what is commonly called the posterior part of tl squamous suture, has always the evident serrat form ; and is therefore reckoned by some (d), a d tinct suture, under the name of additamenlum pos rius suturce squamosce.—I have seen two squamous s tures on the same temple, with a semicircular pif of bone between them (e). We ought here to remark, that the true squamc sort of suture is not confined to the conjunction of I temporal and parietal bones, but is made use of join all the edges of the bones on which each temj Cels,(а) deVesal, re medic, lib. 1.cap. cap. 1.—Laurent. 5. fig. 3. 4. etHist. in text. Anat. cap. lib. 6—Paav 2. cap. usu(б )part. Hippocrat. lib. 9. cap. de vulner.17- capitis, § 1.—Galen, de ossib. & mendosae,* As!r<$««S», harmoniales, •r^rxeXXri/jiura, commissure* in unguem.temporales, cortica monst.(c) Columb. des os. de re Anat. lib. 1. cap. 4—Dionis Anat. 3. (e)(d) Sue,Albin. Trad, de ossib. d’osteolog. § 54. p. 48. OF THE SKELETON. 51 pal muscle is placed (a): For the two parts of the sphe- Idal suture which are continued from the anterior L of the common squamous suture just now de- ibed, of which one runs perpendicularly downwards, l the other horizontally forwards, and also the lower t of the coronal suture, already taken notice of, may be justly said to pertain to the squamous suture.— e manner how I imagine this sort of suture is form- at these places, is, That by the action of the strong nporal muscles on one side, and by the pressure of brain on the other, the bones are made so thin, t they have not sufficient surfaces opposed to each er to stop the extension of their fibres in length, 1 thus to cause the common serrated appearance of ures explained in p. 29, but the narrow edge of the ! bone slides over the other. The squamous form is ) more convenient here; because such thin edges bones, when accurately applied one to another, > ive scarcely any rough surface, to obstruct or hurt le muscle in its contraction ; which is still further ovided for, by the manner of laying these edges on i .ch■ other ; for, in viewing their outside, we see the > mporal bones covering the sphenoidal and parietal, id this last supporting the sphenoidal, while both i ount on the frontal; from which disposition, it is j ident, that while the temporal muscle is contract- g, which is the only time it presses strongly in its Dtion on the bones, its fibres slide easily over the j ternal edges. Another- advantage is, that all this ny part is made stronger by the bones thus sup- 1 rting each other. . i The bones of the skull are joined to those of the Common :e, by schyndelesis and sutures.—The schyndelesis is Sutures, the partition of the nose—The sutures said to be nmon to the cranium and face are five, viz. the moidal, sphenoidal, transverse, and two zygomatic. Parts however of these sutures are at the junction only the bones of the skull. a)sciences, Vesal. 1720.Anat. lib. 1. cap. 6—Winslow, Mem. de 1’acad. c 6 52 OF THE SKELETON. The ethmoidal and sphenoidal sutures surround ti bones of these names; and in some places help make up other sutures, particularly the squamous aJ transverse ; and in other parts there is but one sutu Transverse. commonThe transverse to these twosuture bones. is extended quite across t face, from the external * canthus of one orbit to t same place of the other, by sinking from the canth mountingdown the uponoutside its inside,of the it orbit is continued to its bottomby the root; th the nose down the internal f part of the other orb and rises up again on its outside to the other canth It may be here remarked, that there are some inti ruptions of this suture in the course I have describe for the bones are not contiguous everywhere, but t separated, to leave holes and apertures, to be me ygomatic. tionedTbe hereafter.zygomatic sutures are one on each side, bei short, and slanting from above obliquely downwa: and backwards, to join a process of the cheek-bc to one of the temporal bones, which advances towa: the face; so that the two processes thus united, fo a sort of bridge, or jugum, under which the tempo muscle passes; on which account the processes, £ suture joining them, have been called zygomatic. It must be observed, that the indentations of sutures do not appear on the inside of the cranium, much so strong as on the outside ; but the bones se joined almost in a straight line; nay, in some sku the internal surface is found entire, while the sutu are manifest without; which may possibly be owing the less extent of the concave than of the convex s face of the cranium, whereby the fibres of the ini nal side would be stretched farther out at the ed , of the bones, than the exterior ones, if they were , resisted. The resistances are the fibres of the op > site bone, the parts within the skull, and the dipl t of which the last, being the weakest, the most j vanced fibres or serrce run into it, and leave the c Lateral. E. t Mesial. E. OP THE SKELETON. 53 tiguous edges equal, and more ready to unite ; where- as the serrce of the external table have space enough ibr their admission between the fibres of the opposite bone, and therefore remain of the indented form, and ire less liable to the concretion, whereby the sutures ire obliterated (a).—By this mechanism, there is no •isk of the sharp points of the bones growing inwards, since the external serrce of each of the conjoining Jones rest upon the internal smooth-edged table of he other, and external forces applied to these parts ire strongly resisted, because the sutures cannot yield. Unless the serrated edges of the one bone, and the l 1slain internal plate of the other are broken (6). The advantages of the sutures of the cranium are u { | i hese : 1. That this capsula is more easily formed and sutures.ses 0 t ie Extended into a spherical figure, than if it iiad been me continued bone. 2. That the bones which are at ome distance from each other at birth, might then s field, and allow to the head a change of shape, ac- . pmmodated to the passage in which it is engaged, i Whence, in hard labour of childbed, the bones of the ; ranium, instead of being only brought into contact, re sometimes made to mount one upon another, i. It is alleged, that, through the sutures, there is a transpiration of steams from the brain, which was the ;Id doctrine; or some communication of the vessels (i fithout, and of those within the skull, larger here lan in any other part of the cranium, according to jme moderns ; and therefore cucuphae, fomentations, , ;i itaplasms, cephalic plasters, blisters, are applied, and 1 sues are eroded, or cut in the head, at those places i -here the sutures are longest in forming, and where ; le connexion of the bones is afterwards loosest, for ic cure of phrenitis, mania, inveterate head-ach, epi- psy, apoplexy, and other diseases of the head. The ivourers of the doctrine of transpiration, or commu- ications of vessels at the sutures, endeavour to sup- ort it by observations of persons subject to head- la)(6) Winslow,Hun auk!. MemoirsMemoires de de 1’acad. 1’acad. des des sciences, sciences, 1720. 1730. D 3 54 OP THE SKELETON. achs, which caused death, from the sutures being tt closely united (a). 4. That the dura mater may 1 more firmly suspended by its processes, which insim ate themselves into this conjunction of the bones; f doing this equally, and where there is the greatest n cessity of adhesion, the sutures are disposed at near equal distances, and the large reservoirs of blood, tl sinuses, are under or near them. 5. That fractur might be prevented from reaching so far as they wou in a continued bony substance. 6. That the connexi at the sutures being capable of yielding, the bon might be allowed to separate; which has given gre relief to patients from the violent symptoms whi they had before this separation happened (6). A: it seems reasonable to believe, that the opening of t sutures was of great benefit to several others who we rather judged to have been hurt by it (c) : for i must think, that the consequences of such a force ai ing upon the brain, as was capable of thrusting t bones asunder, must have been fatal, unless it b been thus yielded to. ParticularBones. cranium,Having I gonenow proceedthrough to the examine general each structure bone of ofwhi t that brain-case consists, in the order in which I fi: named them. Bone.Frontal onlyThe bone Os ofFrontis* that part ofhas the its face name we from call tiieforeheiits being t though it reaches a good deal further. It has soi i resemblance in shape to the shell of the concha hiv. i- vis, commonly called the cockle; for the greatest p; iv of it is convex externally, and concave internal itt with a serrated circular edge; while the smaller pi (a) Columb. de re Anat. lib. 1. cap. 5—Verduc. nouv Si; osteologie,(A) Ephemerid. chap. 14. Germanic, Dionis, dec.Anat. 1. 3.aim. demonstr. 4. et 5. desos.observ. 31 j; 10.(c) obs. Ephemerid. 31. Vander Germ. Linden, dec. Medicin.2. ann. 9.phys. obs. cap.230. 8. art.Ibid, 4. cei§ ^' Anat.Hildan. lib. Observ. 3. cap. cent. 6. 1.Pechlin. obs. 1. Observ.cent. 2. obs.lib. 2.7- Observ.Bauhin. 39. The S communis,* Ulrura*, sincipitis. Voiyfiit, coronale, inverecundum, puppis, seni OP THE SKELETON. 55 has processes and depressions, which make it of an irregular figure. The external surface of the osfrontis is smooth at Processes, its upper convex part; but several processes and ca- vities are observable below; for, at each angle of each orbit, the bone juts out, to form four processes, two internal * and as many external t; which, from this situation, may be named angular. Between the in- ternal and external angular processes of each side, is extended an arched ridge, on which the eye-brows are placed. Very little above the internal end of each of these superciliary ridges, a protuberance may be re- marked, in most skulls, where there are large cavi- ties, called siMMses, within the bone; of which hereafter, i-—Betwixt the internal angular processes, rises a small process, which forms some share of the nose, and thence is named nasal.—Some, observe a protuberant part on the edge of the bone behind each external angular [process, which they call temporal processes; but these are inconsiderable From the under part of the su- perciliary ridges, the frontal bone runs a great way , backwards ; which parts may be justly called orbitar processes. These, unlike the rest of this bone, are ii concave externally, for receiving the globes of the eyes, with their muscles, fat, &c. . of Inthe each superciliary of the orbitar ridges, processes, a considerable behind sinuositythe middle is observed, where the glandula innominata Galeni, or la- chrymalis, is lodged.—Behind each internal angular process, may be remarked, a small pit where the car- .] tilaginouseye is fixed. pully Betwixt of the musculusthe two orbitar obliquus processes, major\ ofthere the is a large discontinuation of the bone, into which the . cribriform part of the os ethmoides is incased. The frontal bone frequently has little caverns formed in it here, where it is joined to the ethmoid bone.—Behind each external angular process, the surface of the fron- tal bone is considerably depressed where part of the temporal muscle is placed. i* Mesial.Obliquus E.superior oculi Alb. E. f Lateral. E. D 4 56 OF THE SKELETON. Foramina. The foramina, or holes, observable on the externa] surface of the frontal bone, are three in each side— One in each superciliary ridge, a little removed from its middle towards the nose ; through which a twig oi the ophthalmic branch of the fifth pair of nerves pas- ses out of the orbit, with a small artery from the in- ternal carotid, to be distributed to the teguments and muscles of the forehead.—These vessels in some skulls make furrows in the osfrontis, especially in the bones of children, as has also been observed of another con- siderable vessel of this bone near its middle (a); and therefore we ought to beware of transverse incisions or either side of the osfrontis, which might either oper these vessels, or hurt the nerves while they are yet ir part within the bone ; for, when vessels are thus wounded, it is difficult to stop the haemorrhagy, be- cause the adhesion of a part of the artery to the bone hinders its contraction, and consequently styptics car have little effect; the sides of the furrow keep of he artery; and w< escharotics, becaust they make the bone carious; and nerves thus injurec tosometimes the superciliary produce foramina, violent symptoms. we must remark,But, to that returr of ten, instead of a hole, only a notch is to be seen nay, in some skulls, scarcely a vestige even of this i: left; in others, both hole and notch are observable when the nerve and artery run separately. Frequent ly a hole is found on one side, and a notch on th« other ; at other times we see two holes; or there is s common hole without, and two distinct entries inter- nally. The reason of this variety of a hole, notch, de- pression, or smoothness in the superciliary ridge, ii the different length and tension of the nerves and ves sels ; the shorter they are, the more they are sunk in to the bone as it grows.—Near the middle of the in side of each orbit, hard by, or in the transverse suture is a small hole for the passage of the nasal twig of tin ■ first branch of the fifth pair of nerves, and of a brand >. (a) Ruysch. Mus. anat, theca D. reposit, 4. No, 3, OF THE SKELETON. 57 >f the ophthalmic artery. This hole is sometimes en- irely formed in the os fronlis; in other skulls, the ides of it are composed of this last hone and of the ts planum. It is commonly known by the name of orbi- arium internum, though anterius should be added, be- :ause of the next, which is commonly omitted—This, vhich may be called orbilarium internum posterius, is inch another as the former; only smaller, and about in inch deeper in the orbit; through it a small branch Hif the ocular artery passes to the nose. Besides these fix, a great number of small holes is observable on ri he outer surface of this bone, particularly in the two Protuberances above the eye-brows. Most of these ! Denetrate no further than the sinuses, or the diplo'e, i f the sinuses be wanting; though sometimes I have teen this bone so perforated by a vast number of these ; jmall holes, that, placed between the eye and a clear ight, it appeared like a sieve.—In the orbit of the 11 enerality of skeletons, we may observe one, two, or ►nore holes, which allow a passage to a hog’s bristle hrough the skull. The place, size, and number of ■i hese, are, however, uncertain. They generally serve jbr the transmission of small arteries or nerves. $ The internal surface of the os frontis is concave, ex- Internal ;, :ept at the orbitar processes, which are convex, to Central S mpport the anterior lobes of the brain. This surface Surface, s not so smooth as the external; for the larger branch- es of the arteries of the dura mater make some fur- i 'ows in its sides and back parts. The sinuosities from :* .he luxuriant risings of the brain, mentioned when de- scribing the general structure of the cranium, are of- ,en very observable on its upper part; and its lower . md fore parts are marked with the contortions of the interior lobes of the brain.—Through the middle of j :his internal surface, where always in children, and > sometimes in old people, the bone is divided, either a .'ll ridgeis fastened, stands orout, a furrow to which runs, the in upper which edge the ofupper the falx side of the superior longitudinal sinus is lodged; on both these accounts chirurgical authors justly dissuade the application of the trepan here. The reason of this difference in skulls, is alleged by some authors to be, 58 OF THE SKELETON. that in thin skulls the ridge strengthens the bom and in thick ones there is no occasion for it. To tl way of accounting for this phenomenon, it may jus ly be objected, that generally very thick skulls ha a large spine here, and frequently thin ones have or a furrow. Perhaps this variety may be owing to t different times of complete ossification of those pai in dififerent subjects. For if the two sides of this bo meet before they arrive at their utmost extent growth, they unite very firmly, and all their fibi endeavour to stretch themselves out where there the least resistance, that is, between the hemispher of the brain. To support this reasoning, we may i mark, that those adults, whose frontal bone is divid> by the sagittal suture, never have a ridge in this pla« Immediately at the root of this ridge or furro' there is a small hole, which sometimes pierces throu* the first table, and, in other skulls, opens into the s perior sinus of the ethmoid bone within the nose. . it a little process of the falx is lodged, and a small a tery, and sometimes a vein, runs (a) ; and the sup rior longitudinal sinus begins here.—This hole, hov ever, is often not entirely proper to the osfrontis ; f in several skulls, the lower part of it is formed in tl upper part of the base of the crista galli, which is Compnsi- processThe osof front the ethmoid is is composed bone {b). of two tables, and i tI0n' intermediate diplo'e, like the other bones of the era niui and, in a middle degree of thickness between the occipitis and the parietal bones; is pretty equal dense all through, except at the orbitar processe where, by the action of the eye on one side, and pre sure of the lobes of the brain on the other, it is mat extremely thin and diaphanous, and the meditullium entirely obliterated. Since in this place there is s weak a defence for the brain, the reason appears wl fencers esteem a push in the eye mortal (c). (4)(a) Ingrass.Morgagn. Comment. Adversar. inGralen. 0. animad. de ossib.31. cap. 1. comment) Anat.(c) Ruysch.lib. 3. cap. Observ. 10. Bonet. Anat. Sepulch. Chir. Observ. Anat. fib.54. 4. §Diemerbroecl 3. observ. 1’ OP THE SKELETON. 59 The diplde is also exhausted in that part above the Sinuses, eye-brows, where the two tables of the bone separate, by the external being protruded outwards to form two large cavities, called sinus frontales. These are divided by a middle perpendicular bony partition. Their ca- pacities in the same subject are seldom equal; in some the right, in others the left, is larger—And in differ- ent bones their size is as inconstant; nay, I have ex- amined some, where they were entirely wanting: which oftener happens in such as have a flat forehead, and whose sagittal suture is continued down to the loose, than in others (a)—In some skulls, besides the large perpendicular septum, several bony pillars, or short partitions, are found in each sinus; in others these are wanting. For the most part the septum is entire ; at other times it is discontinued, and the two iinusses communicate. When the sinusses are seen in such skulls as have the frontal bone divided by the Sagittal suture, the partition dividing these cavities is 1 evidently composed of two plates, which easily sepa- itl rate.bole, atEach the sinusinner commonly and lower opens part byof athe roundish internal small an- gular processes, into a sinus formed in the nose, at the upper and back part of the os unguis ; near to which ;here are also some other small sinuses of this bone (6), ;he greater part of which open separately nearer the \ 1 :eptum narium. and often they terminate in the same common canal with the large ones, i? In a natural and sound state, these cavities are of Their us iJ» ionsiderable advantage; for the organ of smelling be- ng thus enlarged, the effluvia of odorous bodies escape ■' t with more difficulty; and their impressions being : nore numerous, are therefore stronger, and affect the )rgan more. That odorous particles may be applied ;o the membrane of the sinuses, is evident from the * ^ain felt in this part of the forehead, when the effluvia *f volatile spirits, or of strong aromatics, are drawn up into the nose by a quick inspiration.—These, and the •ther cavities which open into the nose, increase the > : (6)(a) CowperFallop. Exposit.in Drake’s de Anthropolog.ossibus, cap. 13.book 3. chap. 10. OF THE SKELETON. sound of our voice, and render it more melodious, by serving as so many vaults to resound the notes. Henct people labouring under a coryza, or stoppage of the nose from any other cause, when they are by the vul- gar, though falsely, said to speak through their nose have such a disagreeable harsh voice—The liquor se- parated in the membrane of these sinuses, trickles dowr upon the membrane of the nose to keep it moist. From the description of these sinuses, it is evident; how useless, nay, how pernicious it must be, to apply a trepan on this part of the skull; for this instrument instead of piercing into the cavity of the cranium. would reach no further than the sinuses ; or, if the in- ner table were perforated, any extravasated blood thal happened to be within the skull, would not be dis- charged outwardly, but would fall into the sinuses. there to stagnate, corrupt, and stimulate the sensible membranes; from which also there would be such £ constant flow of glairy mucus, as would retard, if nol hinder a cure, and would make the sore degenerate into an incurable Jislula. Besides, as it would be al- most impossible in this case to prevent the air, pass- ing through the nose, from having constant access tc the dura mater, or brain, such a corruption would be brought on these parts, as would be attended wit! great danger. Further, in respiration, the air rush- ing violently into these cavities of the osfrontis, and passing through the external orifice, whenever it was not well covered and defended, would not only prevenl the closing up of the external orifice, but might other- wise bring on bad consequences (a).—The membrane lining these sinuses is so sensible, that inflammations of it must create violent torture (6) ; and worms, or Connexion. insectsThe uppercrawling circular there, part must of give the greatosfrontis, uneasiness is joined (c). traitd(а) 4.Paaw, chap. de 15. Ossibus, Nouvelle pars. osteologie, 1. cap. 7—Palfyne partie 2. chap. Anatom, 3. chir. serv.(б) 10.Fernet Patholog. lib. 5. cap. 7—Saltzman Decur. ob. cent.(c) 2.Fernel. epist. Patholog.74—Hist, lib. de 5. 1’acad.cap. 7-—Bartholin. des sciences, Epistol.1708 & medic,1733. OF THE SKELETON. 61 to the ossn parietalia, from one temple to the other [ by the coronal suture. From the termination of the j coronal suture to the external angular processes, this bone is connected to the sphenoid by the sphenoidal suture. At the external canthi of the eyes, its angu- lar processes are joined by the transverse suture to the ossa malarum, to which it adheres one-third down the outside of the orbits; whence to the bottom of these cavities, and a little up on their internal sides, these orbitar processes are connected to the sphenoidal bone by that same suture In some few skulls, how- ever, a discontinuation of these two bones appears at the upper part of the long slit, near the bottom of the orbit.—On the inside of each orbit, the orbitar process is indented between the cribriform part of the ethmoid bone, and the os planum and unguis—The transverse suture afterwards joins the frontal bone to the superior nasal processes of the ossa maxillaria superiora, and to the nasal bones. And, lastly, its nasal process is il connected to the nasal lamella of the ethmoid bone. The frontal bone serves to defend and support the Uses.. ns anterior lobes of the brain. It forms a considerable : part of the cavities that contain the globes of the \ eyes, helps to make up the septum narium, organ of fil smelling, &c From the description of the several i parts, the other uses of this bone are evident. In a ripe child, the frontal bone is divided through State at the middle ; the superciliary holes are not formed; Birth. ,! aften a small round piece of each orbitar process, be- , i hind the superciliary ridge, is not ossified, and there .• s no sinus to be seen within its substance. Each of the two ossa parietalia,* or bones serv- Parietal ng as walls to the encephalon, is an irregular square ; Bones, ts upper f and fore j; sides being longer than the one > lehind || or below IT. The inferior side is a concave irch ; the middle part receiving the upper round part »f the temporal bone.—The angle, formed by this upper side and the fore one, is so extended, as to have i Be appearance of a process. ! * Kofufm, paria, sincipitis, verticis, arcualia, nervalia, cogita- ' .< iionis,+ Mesial. rationis, E. bregmatis,$ Glabellar. medefactionis. E. || Iniad. E. Basilad. E. OF THE SKELETON. Surface.External UponThe it,external somewhat stirface below of each the osmiddle parietale height is convex. of the bone, there is a transverse arched ridge, generally of a whiter colour than any other part of the bone ; from which, in bones that have strong prints of muscles, we see a great many converging furrows', like so many radii drawn from a circumference towards a centre. From this ridge of each bone the temporal muscle rises ; and, by the pressure of its fibres, occasions the furrows just now mentioned Below these, we ob- serve, near the semicircular edges, a great many ris- ings and depressions, which are joined to like inequa- lities on the inside of the temporal bone, to form the squamous suture. The temporal bone may therefore serve here as a buttress, to prevent the lower side ol the parietal from starting outwards when its upper part is pressed or struck, (a). Foramen. Near the upper side of these bones, towards the hind part, is a small hole in each, through which a vein passes from the teguments of the head to the longitudinal sinus. Sometimes I have seen a brand: of the temporal artery pass through this hole, to be distributed to the upper part of ihejalx, and to the dura mater at its sides, where it had frequent anasto- moses with the branches of the arteries derived froir the external carotids, which commonly have the name of the arteries of the dura mater, and with the branches of the internal carotids, which serve the falx. In se veral skulls, one of the ossa parielalia has not this hole in others, there are two in one bone: and in some nol one in either. Most frequently this hole is through both tables; at other times the external table only is perforated—The knowledge of the course of these ves- sels may be of use to surgeons, when they make am incision near this part of the head, lest, if the vessel are rashly cut near the hole, they shrink within the sub stance of the bone, and so cause an obstinate haemor- rhagy, which neither ligatures nor medicines can stop Surface.Internal On the inner concave surface of the parietal bones (a) Hunauld. in Mem. de 1’acad. des sciences, 1730. OF THE SKELETON. we see a great many deep furrows, disposed somewhat like the branches of trees. The furrows are largest and deepest at the lower edge of each os parietale, es- pecially near its anterior angle, where sometimes a full canal is formed. They afterwards divide into small furrows, in their progress upwards.—In some skulls a large furrow begins at the hole near the up- per edge, and divides into branches, which join with those which come upwards, showing the communica- tions of the upper and lower vessels of the dura mater. —In these furrows we frequently see passages into the diplo'e: and sometimes I have observed canals joing off, which allowed a small probe to pass some | inches into the bony substance. Some (a) tell us, that they have observed these canals piercing the bone towards the occiput—On the inside of the upper edge of the ossa parietalia, there is a large sinuosity, ! frequently larger in the bone of one side than of the other, where the upper part of the falx is fastened, and the superior longitudinal sinus is lodged.—Gene- rally part of the lateral sinuses makes a depression near the angle, formed by the lower and posterior sides of these bones; and the pits made by the pro- minent parts of the brain are to be seen in no part of the skull more frequent, or more considerable, than in the internal surface of the parietal bones. The ossa parietalia are among the thinnest bones Substance, of the cranium; but enjoy the general structure of two tables and diploe most completely, and are the most equal and smooth. These bones are joined at their fore-side to the os Connexion. frontis by the coronal suture ; at their long inferior angles, to the sphenoid bone, by part of the suture of this name ; at their lower edge, to the ossa temporum, by the squamous suture, and its posterior additamen- \ 'um; behind, to the os occipitis, or ossa triquetra, by . the lambdoid suture ; and above, to one another, by , the sagittal suture. They have no particular uses besides those men- Uses. (a) Cowper, Anatom, explic. of 90. tab. fig. 64 OF THE SKELETON. tioned in the description of their several parts, except what are included in the account of the general struc- ture of the cranium. In a child born at the full time, none of the sides of this bone are completed; and there never is a hole in the ossified part of it near to the sagittal suture. Bregma. The large unossified ligamentous part of the cra- nium observable between the parietal bones, and the middle of the divided os frontis of new-born children, called by the vulgar the open of the head, was ima- gined by the ancients to serve for the evacuation of the superfluous moisture of the brain; and therefore they named it bregma*, or the fountain; sometimes adding the epithet pulsatilis, or beating, on account of the pulsation of the brain felt through this flexible ligamento-cartilaginous substance. Hence very fre- quently the parietal bones are called ossa bregmatis. The upper middle part of the head of a child, in a natural birth, being what presents itself first at the os uteri (a), an accoucheur may reach the bregma with his finger, when the os uteri is a little opened If the bregma be stretched, and the pulsation of the brain be felt through it, the child is certainly alive; but if it be shrivelled and flaccid, without any ob- servable pulsation in it, there is some reason to sus- pect the child to be very weak, or dead. Those whc practise midwifery should therefore examine the state of the bregma accurately. All the bregma is generally ossified before sever years of age. Several authors (6) say, they have ob- served it unossified in adults; and physicians, who or- der the application of medicines at the meeting of thi coronal and sagittal sutures, seem yet to think that : derivation of noxious humours from the encephalon i more easily procured at this part than any other of th< skull; and that medicines have a greater effect her* than elsewhere, in the internal disorders of the head. * Palpitans vertex, foliolum, folium, triangularis lacuna. chap.(«) 1.Burton’s § 5. Midwifery, § 51.—Smellie’s Midwifery, book 1 Anat.(A) Bartholin.lib. 9. cap. Anat.C.—Kerkring. reform, lib.Osteogen, 4. cap. cap.6.—Diemerbroecb 2. OF THE SKELETON. 65 OSSA TEMPORUM*, so named, say authors. Temporal from the hairs first becoming grey on the temples,Bones- md thus discovering people’s ages, are each of them ‘qual and smooth above, with a very thin semicircu- iar edge; which, from the manner of its connexion vith the neighbouring bones, is distinguished by the iame of os squamosum.—Behind this, the upper part of ' he temporal bone is thicker, and more unequal, and s sometimes described as a distinct part, under the ;ame of pars mammillaris (a).—Towards the base of he skull, the temporal bone appears very irregular and i mequal; and this part, instead of being broad, and . daced perpendicularly, as the others are, is contract- d into an oblong very hard substance, extended ho- izontally forwards and inwards t, which in its pro- cess becomes smaller, and is commonly called os pe- i rosum. Three external processes of each temporal bone are PExternalrocesses jenerally described.—The first placed at the lower ’ . nd hind part of the bone, from its resemblance to a . ipple, is called masloides, or mammillaris. It is not so- d, but within is composed of cancelli, or small cells, 'hich have a communication with the large cavity of le ear, the drum ; and therefore sounds, being mul- , plied in this vaulted labyrinth, are increased, before , icy are applied to the immediate organ of hearing. .. Into the mastoid process, the sternomastoideus mus- ic is inserted; and to its hack part, where the sur- ice is rough, the trachelomastoideus, and part of the olenius are fixed.—About an inch farther forward, le second process begins to rise out from the bone; . id having its origin continued obliquely downwards id forwards for some way, it becomes smaller, and , stretched forwards to join with the os malce ; they ►gether forming the hony jugum, under which the ;mporal muscle passes. Hence this process has been oralia,Kgora^aiv, lapidosa, xoatruv, mendosa, xogguv, dura, XsxiltuSri, arcualia, xokiuiik, tymparum, Xitttdn, armalia, tem- .xea,(a) parietalia.Albin, de ossib. § 26. t Mesiad. E. OF THE SKELETON. named zygomatic*. Its upper edge has the stron aponeurosis of the temporal muscle fixed into it; and il i lower part gives rise to a share of the masseter.—Th . fore-part of the base of this process is an oblong tr bercle, which in a recent subject is covered with smooth polished cartilage, continued from that whic » lines the cavity immediately behind this tubercle,- from the under craggy part of the os temporum, the thir n process stands out obliquely forwards. The shape < tl it is generally said to resemble the ancient stylus serif torius; and therefore it is called the styloid process') Some authors (a) however contend, that it ought I be named steloid, from its being more like to a pilla Several muscles have their origin from this proces and borrow one-half of their name from it; as styh glossus, stylo-hyoideus, stylo-pharyngeus; to it a ligj ment of the os hyoides is sometimes fixed; and anoth< is extended from it to the inside of the angle of the lou er jaw. This process is often even in adults not ei tirely ossified, but is ligamentous at its root, and somi times is composed of two or three distinct pieces.- Round the foot of it, especially at the fore-part, the: is a remarkable rising of the os petrosum, which son; have esteemed a process ; and from the appearance makes with the styliform, have named it vaginalis.- Others again have, under the name of auditory proces reckoned among the external processes that semici: cular ridge, which, running between the root of tl: mastoid and zygomatic processes, forms the under-pai of the external meatus auditorius. sions.Depres- faceThe of sinuositieseach os temporum or depressions are these:—A on the external long^/bssa sui s the inner and back part of the root of the mamillai process, where the posterior head of the digastric muscle has its origin.^—Immediately before the ro( * Kayxfuf, paris, ansa: ossium temporum, ossa arcualia, parii jugalia,-|- rgai0«i$», conjugalia. (itXtmihn ‘TXnxT^i, os calaminum, sagittate, cli vale,(a) acuale,Galen, calcarde usu capitis.part. lib. 2. cap. 4.—Fallop. Observ. anatos X Biventer maxilla:. Alb. E. OP THE SKELETON. 67 of the zygomatic process, a considerable hollow is left, for lodging the crotaphite * muscle—Between the zy- gomatic, auditory, and vaginal processes, a large cavi- ty is formed ; through the middle of which, from top to bottom, a fissure is observable, into which part of the ligament that secures the articulation of the lower jaw with this bone is fixed. The fore-part of the ca- vity being lined with the same cartilage which covers the tubercle before it, receives the condyle of the jaw ; r and in the back-part a small share of the parotid gland si and a cellular fatty substance, are lodged.—At the inside of the root of the styloid apophyse, there is a thimble-like cavity, where the beginning of the inter- nal jugular vein, or end of the lateral sinus is lodg- , ed—And as the sinuses of the two sides are frequent- ly of unequal size ; so one of these cavities is as often larger than the other (a).—Round the external meatus auditorius, several sinuosities are formed for receiving ( the cartilages and ligaments of the ear, and for their firm adhesion. eachThe of holes these that bones, commonly and are appearproper onto theeach outside of them, of Foramina. i are five—The first, situated between the zygomatic i. and mastoid processes, is the orifice of a large funnel- i like canal, which leads to the organ of hearing, and therefore is called meatus auditorius externus t.—The second gives passage to the portio dura of the seventh pair of nerves, and from its situation between the mas- , toid and styloid processes, is called foramen stylo-mas- toideum%. Some way before, and to the inside || of the styloid process, is the third hole; the canal from which runs first upwards, then forwards, and receives into it the internal carotid artery, and the beginning of the intercostal nerve : where this canal is about to make . the turn forwards, one or sometimes two very small ! holes go off towards the cavity of the ear called tym- panum : through these Valsalva (6) affirms the pro- * Temporal muscle. E. (а)XIoj«s Hunauld. res uxstit, in Mem. soo! rat de arat,1’acad. fenestra des sciences, aurium. 1730. $(б Aquaeductus) De aure humana, Fallopii. cap. 2. § ||22. Mesiad. et tab. 7-E. fig. !• OF THE SKELETON. per artery or arteries of that cavity are sent—On thi anterior edge of this bone, near the former, a fourt) hole is observable, being the orifice of a canal whicl runs outwards and backwards, in a horizontal direc- tion, till it terminates in the tympanum. This in tin recent subject, is continued forward and inward, fron the parts which I mentioned just now as its orifice ir the skeleton, to the side of the nostrils ; being parth cartilaginous, and partly ligamentous. The whole ca nal is named. Iter a palato ad aurem, or Eustachian tube.—On the external side of the bony part of this canal, and above the chink in the cavity that receives the condyle of the lower jaw, is the course of the litth nerve said commonly to be reflected from the lingua branch of the fifth pair, till it enters the tympanum to run across this cavity, and to have the name o: chorda tympani—The Jifth hole is very uncertain appearing sometimes behind the mastoid process sometimes it is common to the temporal and occipital bones; and in several skulls there is no such hole The use of it, when found, is for the transmission o: a vein from the external teguments to the lateral sinus: But, in some subjects, a branch of the occipital artery passes through this hole, to serve the back-part of the dura mater ; in others, I have seen two or three such holes : But they are oftener wanting than found And we may, once for all, in general, remark, that the largeness, number, situation, and existence of all such holes, that for the most part allow only a passage foi verveins from without to the internal receptacles, are Internal 7 uncertain.nterna Surface. equal ; ^the upper^ surface circular of edge the ofossa the temporum squamous is pariun- having numerous small ridges and furrows for its con- junction with the parietal bones; and the rest of it is irregularly marked with the convolutions of the middle part of the brain, and with furrows made by the branches of the arteries of the dura mater. Portion transverseFrom the hard under craggy part of protuberancethis internal surface, runs horizon-a larger tally inwards and forwards, with a sharp edge above, OF THE SKELETON. and two flat sides, one facing obliquely forwards and outwards *, and the other as much backwards and in- wards f. To the ridge between these two sides, the large lateral process of the dura mater is fixed. Sometimes a small bone resembling a sesamoid, is found between the small end of this petrous pro- cess and the sphenoid bone (a). 1 owards the back-part of the inside of the os tem- j porum, a large deep fossa is conspicuous, where the ; lateral sinus lies; and frequently on the top of the petrous ridge, a furrow may be observed, where a ; small sinus'is situated. The internal proper foramina of each of these bones Foramina, •are, first, the internal meatus auditorius in the poste- rior plain side of the petrous process. This hole soon divides into two; one of which is the beginning of the aquceduct of Fallopius ; the other ends in several very small canals [b), that allow a passage to the : branches of the portio mollis of the seventh pair of nerves, into the vestibule and cochlea. Through it al- so an artery is sent, to be distributed to the organ of hearing.—The second hole, which is on the anterior , plain side of the craggy process, gives passage to a ’ reflected branch of the second branch of the fifth pair jf nerves, which joins the portio dura of the auditory ", nerve,■ while it is in the aquceduct (c), small branches of blood-vessels accompanying the nerves or passing ' through smaller holes near this one.—The passage of •: ;he cutaneous vein into the lateral sinus, or of a branch j of the occipital artery, is seen about the middle of the , arge fossa for that sinus; and the orifice of the canal of the carotid artery is evident at the under part of ' ;he point of the petrous process. '! Besides these proper holes of the temporal bones i .vhich appear on their external and internal surfaces, * Glabellad and laterad. E. f Iniad and mesiad. E. iion(а )Anatomique Riolan. Comment, du corps de humain, ossib. cap.trait, 32—Winslow. des os secs. § 26G.Exposi- ((c)б) Valsalv. de aureaure, humana, cap. 3. §cap. 10. 3. § 11. 70 OF THE SKELETON. there are two others in each side that are common tc this bone and to the occipital and sphenoidal hones which shall be mentioned afterwards in the descriptior of these bones. The upper round part of the squamous bones is thin but equal; while the low petrous part is thick anc strong, but irregular and unequal, having the distinc- tion of tables and diploe confounded, with several cavi- ties, processes, and bones within its substance, whicl: are parts of the organ of hearing. That a clear ide: may be had of this beautiful, but intricate organ, ana tomists generally choose to demonstrate all its parti together. I think the method good; and therefore since it would be improper to insert a complete trea tise ontheear here, shall omit the description of the part contained within the os petrosum of the skeleton (a) Connection. The temporal bones are joined above to the parieta bones by the squamous sutures, and their posterio additamenta; before, to the sphenoid bone by the su ture of that name •, to the cheek-bones by the zygoma tic sutures ; behind, to the occipital bone, by the lamb doid suture and its additamenta; and they are articulat ed with the lower-jarv in the manner which shall b> described when this bone is examined. U . The purposes which these two bones serve, ar> ses easily collected, from the general use of the cranium and from what has been said in the description of thei several parts. Birth.S»te at tweenIn an the infant, thin uppera small part, fissure and isthe to lower be observed craggy par be of each of these bones; which points out the recen union of these parts.—Neither mastoid nor styloid pro cesses are yet to be seen Instead of a bony funnel like external meatus auditorius, there is only a smootl bony ring, within which the membrane of the drun is fastened.—At the entry of the Eustachian tube, thi side of the tympanum is not completed.—A little mori outward than the internal auditory canal, there is s deep pit, over the upper part of whose orifice the in. (a) See Albini Annotat. Academ. vol. 1. E. OF THE SKELETON. 71 terior semicircular canal of the ear is stretched; and some way below this, the posterior semicircular canal dso appears manifestly. Os Occipitis,* so called from its situation, is con-Occipital rex on the outside, and concave internally. Its figure Bone, s an irregular square, or rather rhomboid; of which he angle above is generally a little rounded ; the two ateral angles are more finished, but obtuse ; and the ower is stretched forward in form of a wedge, and i hence is called by some the cuneiform process.—If ' me would, however, be very nice in observing the everal turns which the edges of the os occipitis make, ,.i ve or seven sides and as many angles of this bone ,' aight be described. The external surface is convex, except at the cunei- External arm apophyse, where it is flatted. At the base of this Surface, j riangular process, on each side of the great hole, but : lore advanced forwards than the middle of it, appear he large oblong protuberances, named the condyles, p serve for the articulation of this bone with the first ertebra of the neck. The smooth surface of each of Condyles, hese condyloid processes is longest from behind for- 1 wards, where, by their oblique situation, they come mch nearer to each other than they are at their back art. Their inner t sides are lower than the external J, ‘ y which they are prevented from sliding to either ; de out of the cavities of the first vertebra (a). In >me subjects each of these plain smooth surfaces seems > be divided by a small rising in its middle; and the ; iwer edge of each condyle, next the great foramen, discontinued about the middle, by an intervening ' otch ; whence some (6) allege that each of these nophyses is made up of two protuberances.—Round i leir root a small depression and spongy roughness are iservable, where the ligaments for surrounding and ' icuring their articulations adhere.—Though the mo- on of the head is performed on the condyles, yet the - mbde.* Xwov, basilare, prorae,f Mesial. memoriae, E. pixidis, fibrosum,+ Lateral. nervosum, E. (a)(4) Galen,Diemerbroeck, de usu part.Anat. lib. lib. 12. D. cap. 6.7- 72 OF THE SKELETON. centre of gravity of that globe does not fall betwee them, but is a good way further forward; from whi< mechanism it is evident that the muscles which pu the head back, must be in a constant state of contra' tion; which is stronger than the natural contractk of the proper flexors, else the head would always fa forwards, as it does when a man is asleep, or labou under a palsy, as well as in infants, where the weigl of the head far exceeds the proportional strength these muscles. This seeming disadvantageous situ; tion of the condyles is however of good use to us, t allowing sufficient space for the cavities of the mou( and fauces, and for lodging a sufficient number muscles, which commonly serve for other uses; bi may at pleasure be directed to act on the head, ar then have an advantageous lever to act with, so as • be able to sustain a considerable weight appended, ' other force applied, to pull the head back. Depres- Somewhat more externally * than the condyles, the: Ridges.sions ami whichis a small makes rising part and of thesemilunated holes, common hollow to inthe each occipit sid and petrous bones.—Immediately behind this, on eac side, a scabrous ridge is extended from the middle the condyle, towards the root of the mastoid proces Into this ridge the musculus lateralis f commonly a cribed to Fallopius, is inserted.—About the middle Arches. the external convex surface, a large arch runs across tl bone; from the upper lateral parts of which the occ pital muscles have their rise; to its middle the trap zii are attached; and half way between this and tl great hole, a lesser arch is extended.—In the hollov- between the middle of these arches the complexi a inserted ; and in the depressions more external ai further forward than these, the splenii are inserted.- 1 Between the middle of the lesser arch and the gre hole, the little hollow marks of the recti minores J aj ; pear; and on each side of these the fleshly inse • tions of the obliqui superiores and recti majores * Laterad. E. -f Rectus capitis lateralis, Alb. 1 §J Recti capitis postici majores.minores. Alb.Alb. E.E. OF THE SKELETON. 73 (make depressions.—Through the middle of the two arches a small sharp spine is placed, which serves as , some sort of partition between the muscles of differ- snt sides, or rather is owing to the action of the mus- :les depressing the bone on each side of it, while this I aart is free from their compression. These prints of , ,he muscles on this bone are very strong and plain in li.ome subjects, but are not so distinct in others—All . ound the great foramen the edges are unequal, for he firmer adhesion of the strong circular ligament i vhich goes thence to the first vertebra One end of .] ach lateral or moderator ligament of the head, is fixed 0 a rough surface at the fore part of each condyle, ; nd the perpendicular one is connected to a rough part i f the edge of the great hole between the two condyles. 1 -Immediately before the condyles, two little depres- ions are made in the external surface of the cuneiform rocess, for the insertion of the recti anteriores minores* i mscles, which are unjustly ascribed to Corvper: and dll further forward, near the sphenoid bone, are two ;her such depressions, for the reception of the recti iteriores majores^—When we consider the size of ic prints of muscles on the occipital bone, before and }hind its condyles, and, at the same time, compare icir distances from these centres of motion of the : jad, we must see how much stronger the muscles are hich pull the head backwards, than those are which j ;nd it forward; and how much greater force the for- ; er acquire by the long lever they act with, than the : tter which are inserted so near the condyles. This eat force in the extensor muscles is altogether ne- ssary, that they might not only keep the head from lling forward in an erect posture, but that they might pport it when we bow forward in the most necessa- > offices of social life, when the weight of the head • mes to act at right angles on the vertebrae of the sck, and obtains a long lever to act with. On the inner surface of the os occipitis we see two ■ *-f- RectiRecti capitiscapitis interniinterni minores.majbres. Alb. E. 74 OF THE SKELETON. ridges ; one standing perpendicular, the other runnii horizontally across the first. The upper part of i. perpendicular limb of the cross, to which the Jala fixed, is hollowed in the middle, or often on one sic for the reception of the superior longitudinal sinus, ai the lower part of it has the small or third process the dura mater fastened to it, and is sometimes h« lowed by the occipital sinus. Each side of the ho; zontal limb is made hollow by the lateral sinuses i closed in the transverse process of the dura mater; t fossa in the right side being generally a continuati of the one made by the longitudinal sinus in the pc pendicular limb, and therefore is larger than the L one (a).—Round the middle of the cross there are fa large depressions separated by its limbs; the two u per being formed by the back part of the brain, a the two lower by the cerebellum.—Farther forwa than the last-mentioned depressions, is the lower p« of the Jbssa for the lateral sinus on each side.—-T inner surface of the cuneiform apophyse is made cc cave for the reception of the medulla oblongata, and the basilar artery—A furrow is made on each si« near the edges of this process, by a sinus of the du Foramina. mater,The whichholes ofempties this bone itself are into commonly the lateral five sinus prop (. and two common to it and to the temporal bones. The first of the proper holes, called foramen magnu from its size, is immediately behind the wedge-li process, and allows a passage to the medulla oblonga nervi accessorii, the vertebral arteries, and sometixr to the vertebral veins.—At each side of this great he near its fore-part, and immediately above the condyl we always find a hole, sometimes two, which sc unite again into one that opens externally; throu these the ninth pair of nerves go out of the skull. The fourth and fifth holes pierce from behind the a dyle of each side into the fossa: of the lateral simist they serve for the passage of the cervical veins to th« (A)(a) Albin.Morgagn. de ossib.Advers. § 65. anat. 6.* animad.Rachitidis, ]. MeduUee spina OF THE SKELETON. 75 nuses. Often one of these holes is wanting, some- mes both, when the veins pass through the great ramen—Besides these five, we frequently meet with her holes near the edges of this bone, for the trans- ission of veins ; but their number and diameter are iry uncertain. The two common foramina are the rge irregular holes, one on each side, between the ’ les of the cuneiform process, and the edges of the ' trous bones. In a recent subject, a strong membrane : ns across from one side to the other of each of these les; in some heads I have seen this membrane os- t ied, or a bony partition dividing each hole ; and, in e greater number of adult skulls, there is a small irp-pointed process stands out from the os pelrosum, d a more obtuse rising in the occipital bone, between ' iich the partition is stretched. Behind this partition, ere the largest space is left, the lateral sinus has its •t1 isage; and before it the eighth pair of nerves and " 'essorius make their exit out of the skull; and some thors say, an artery passes through this hole, to be 1 itowed on the dura mater. ;■ The occipital bone is among the thickest of the era- Substance. rn, though unequally so; for it is stronger above, 1 ere it has no other defence than the common tegu- ‘i nts, than it is below, where, being pressed by the < es of the brain and cerebellum on one side, and by ■ action of the muscles on the other, it is so very ; 1 a, as in many skulls to be diaphanous: But then se muscles ward off injuries, and the ridges and " ies, which are frequent here, make it sufficiently : mg to resist ordinary forces. The tables and diplue : J: tolerably distinct in this hone, except where it is ; bin as to become diaphanous. he occipital bone is joined above to the o»sa pa- Connexion, s ■ alia and triquetra when present, by the lambdoid ire;—laterally to the temporal bones, by the ad- - menta of the lamhdoid suture;—below to the sphe- T bone, by the end of its cuneiform process, in the '€ way that epiphyses and their bones are joined: in children a ligamentous cartilage is interposed veen the occipital and sphenoid bones, which gra- e 2 76 THE SKELETON. dually turns thinner, as each of the bones advanct till their fibres at last run into each other; and, abo sixteen or eighteen years of age, the union of the two bones becomes so intimate, that a separation ca not be made without violence.—The os occipitis joined by a double articulation to the first vertebra the neck, each condyle being received into a superi oblique process of that vertebra. What motion is s lowed here, we shall consider afterwards, where t Uses. vertebraeThe uses are of described. this bone appear from the preceding cl scription, and therefore need not be repeated. Birth.State at vided,An infantby unossified born at cartilages,the full time, into hasfour thisparts.—T bone « first of these is larger than the other three, is of a t angular shape, and constitutes all the part of the bo above the great foramen. Generally fissures appe in the upper part and sides of this triangular boi when all the cartilage is separated by maceratio and sometimes little distinct bones are seen towai the edges of it.—The second and third pieces of tl bone are exactly alike, and situated on each side the great, foramen ; from which very nearly the whi condyles are produced; and they are extended fi wards almost to the fore part of the hole for the nir pair of nerves —The fourth piece is the cuneifo: process, which forms a small share of the great he . and of those for the ninth pair of nerves, and of ! e condyles ; and betwixt it and the sphenoid bone a c: , tilage is interposed. Of the eight bones which belong to the cranii* . there are only two which are not yet described, v , the ethmoid and sphenoid. These we already mentii , ed, in complaisance to the generality of writers on t. , subject, as bones common to the cranium and fa because they enter into the composition of both : l „ the same reason might equally be used for calling 1 frontal bone a common one too. I shall, however, p , by any idle dispute about the propriety of rangi them, and proceed to examine the structure of 1 1 bones themselves. OF THE SKELETON. 77 Os Ethmoides*, or the sieve-like bone, has got its Ethmoid ame from the great number of small holes with which Bone, mt part of it first taken notice of is pierced. When lis bone is entire, the figure of it is not easily describ- 1; but, by a detail of its several parts, some idea ‘ istinguishay be afforded it into of the the cribrijorm whole; andlamella therefore with itsI shallpro- 2ss, the nasal lamella, cellulce, and ossa spongiosa. * ‘ The thin horizontal lamella, is all (except its back Cribriform art) pierced obliquely by a great number of smallp,ate- - >les, through which the filaments of the olfactory ;rves pass. In a recent subject, these holes are so osely lined by the dura mater, that they are much CrtslaGalh. - !ss conspicuous than in the skeleton.—From the mid- - e of the internal f side of this place, a thick process Ises upwards, and being highest at the fore part, i-adually becomes lower, as it is extended backwards, rom some resemblance which this process was ima- ged to have to a cock’s comb, it has been called cris- galli J. The falx is connected to its ridge, and to ic unperforated part of the cribriform plate.—When 5ii e crista is broken, its base is sometimes found to be dlow, with its cavity opening into the nose (a).— - amediately before the highest part of this process, is i'S e blind hole of the frontal bone, which, as was for- merly remarked, is often in a good measure formed by : notch in the fore part of the root of the crista. asal i rFrom the middle of the outer surface of the cribri- Plate^ i m lamella, a thin solid plate is extended downwards ' d forwards, having the same common base with the | Ista galli. Generally it is not exactly perpendicu- -, but is inclined to one side ©r other, and therefore i rides the cavity of the nose unequally. Its inclina- • m to one side, and flexure in the middle, is some- : nes so great, that it fills up a large share of one of i e nostrils, and has been mistaken for a polypus there. I It is thin at its rise, and still rather thinner in its ddle; yet afterwards, towards its lower edge, it * Cribriforme, areiyuihns, spongiforme, cristatum, |» Coronal. Palfyn, E. Anat. $chir. Verruca tr. 4. predura, chap. 15. septum ossis spongiosi. E 3 78 OF THE SKELETON. becomes thicker, that its conjunction with the boi Celulla. andAt middle a little cartilage distance of from the noseeach mightside of be this firmer. exterj process, a cellular and spongy bony substance deper from the cribriform plate. The number and figure the cells in this irregular process of each side, are vt uncertain, and not to be represented in words ; 01 the cells open into each other, and into the cavity the nose. The uppermost, which are below the ap' OssaPlarw. tureThe outerof the surfacefrontal ofsinuses, these arecells formed is smooth like andfunnels. pla where this bone assists in composing the orbit ; which place, on each side, it has got the name of planum; on the upper edge of which, a small nol or two may sometimes be observed, which go to t formation of the internal orbitar holes; as was : Superior markedBelow in the the cells description of each side,of the a thin frontal plate bone. is extend Bones?' inwards,and of a spongyand then texture.—This bending down, spongy it becomes part is trkth: gular, with a straight upper edge placed horizontal an anterior one slanting from above, downwards a forwards, and with a pendulous convex one below. The upper and lower edges terminate in a sharp po behind—The side of this pendulous spongy part ne to the septum narium is convex, and its external s: is concave.—These two processes of the ethmmd be have got the name of ossa spongiosa, or turbinata . Connexion. periora,All the from prominences, their substance, cavities, figure, and meandersand situation. of t ethmoid bone, are covered with a continuation of II membrane of the nostrils, in a recent subject.—i horizontal cribriform plate is lodged between the « bitar processes of the frontal bone, to which it is jo ed by the ethmoid suture, except at the back-pa where it is connected with the cuneiform bone, b’ . suture common to both these bones, though it is j; • nerally esteemed part of the sphenoidal.—Where 1 ossa plana are contiguous to the frontal bone witl t the orbit, their conjunction is reckoned part of t transverse suture.—Farther forward than the oi OF THE SKELETON. 79 olana, the cells are covered by the ossa unguis, which ,re not only contiguous to these cells, but cannot be leparated from them, without breaking the bony sub- itance; and therefore, in justice, those bones ought ;o be demonstrated as part of the ethmoid bone.—Be- i owpongiosa the ossa are unguisoverlapped and plana,by the thesemaxillary cells bonesand ossa The cellular part of each palate bone is contiguous to i :ach os planum and cells backwards—The lower edge »f the nasal perpendicular plate is received into the ■ urrow of the vomer.—Its posterior edge is joined to he fore-part of the processus azygos of the sphenoid ijione—Its upper edge joins the nasal process of the 11 rontal and nasal bones, and its interior one is con- lected to the middle cartilage of the nose. I r From all which, the uses of this bone are evident, Uses. iz. to sustain the anterior lobes of the brain ; to give •; ! jassage to the olfactory nerves, and attachment to the i "alx ; to enlarge the organ of smelling, by allowing • he membrane of the nose a great extent; to sraiten i he passage of the air through the nose, by leaving jmly a narrow winding canal, on the sensible mem- iranous sides of which the substances conveyed along . v:i vith the air must strike; to form part of the orbit of S ;he eyes and septum narium: while all its parts are so . jight as not to be in hazard of separating by their , veight; and they are so thin, as to form a large sur- face, without occupying much space This brittle I mbstance, however, is sufficiently protected from ex- : ernal injuries by the firm bones which cover it. If this bone is attacked by any corroding matter, Diseases. .. ve may easily conceive what destruction may ensue. . Hence it is, that an ozaena is difficult to cure; and j;hat, in violent scurvies, or in the lues venerea, thefa- j uric of the nose, the eyes, and life itself, are in danger. —The situation of the nasal plate may shew us, how langerous a fracture of the bones of the nose may be, . i vhen made by a force applied to their middle fore-part, •f a person in whom this nasal plate is perpendicular. The ethmoid bone of ripe children is divided into s at i wo, by a perpendicular cartilage, which, when ossi- Birth.tate e 4 OF THE SKELETON. fied, is the crista galli, and nasal plate : but its othe: parts are ossified and complete. Sphenoid Os Sphenoides «, or wedge-like bone, so called be Bone. cause of its situation in the middle of the bones of th: cranium and face, is of such an irregular figure, tha I know not any thing to which it may be likened unless, perhaps, it bear some faint resemblance to s ' bat with its wings extended. External When we view the external surface of the os sphe Surface. noides, two or three remarkable processes from eacl . side of it may be observed, which are all of then »f Processes. again subdivided The first pair form the two largi j. lateral processes or wings; the upper part of each o ^ which is called the temporal process, because the- join with the temporal bones in forming the temples ' and the seat for some share of the crotaphite t muscles: tu That part of the wings which juts out towards tin inside, somewhat lower than the temporal apophyses , and is smooth and hollowed, where it makes up pari u of the orbit, is thence named orbitarprocess. Behinc the edge, separating these two processes, there is ofter a small groove, made by a branch of the superioi . maxillary nerve, in its passage to the temporal muscle The lowest and back part of each wing, which runs out sharp to meet the ossa petrosa, has been styled , • the spinous process ; from near the point of which i ,1 sharp-pointed process is frequently produced down- . wards, which some call styliform, that affords origir to the ptery-staphylinus externus J muscle. From this styloid process a very small groove is extended along j the edge of the bone to the hollow at the root of the ( internal plate of the following processes, which forms ; part of the Eustachian tube (a)—The second pair oi 1 external processes of the cuneiform bone is the twc V which stand out almost perpendicular to the base oJ the skull. Each of them has two plates, and a middle r lati,* Cuneiforme,colatorii, cavilla, •roXtiittfin, basilare. multiforme, paxillum, cribratum pa- 1 $f PartTemporal of Circumflexus muscles. E.Palati. Alb. E. des(a) os Winslow,secs, § 233. Exposition anatomique du corps humain, traitt * OF THE SKELETON. 81 fossa facing backwards, and should, to carry on our >mparison, be likened to the bat’s legs, but are com- lonly said to resemble the wings of that creature; id therefore are named pterygoid or aliform * pre- sses. The external t plates are broadest, and the iternal | are longest. From each side of the exter- tal plates, the pterygoid muscles take their rise. At he root of each internal plate, a small hollow may remarked, where the musculus ptery-staphylinus in- •nus, or circumjlexus palati rises, and some share of le cartilaginous end of the Eustachian tube rests; nd, at the lower end of the same plate, is a hook-like ising or process, round which the tendon of the last lamed muscle plays, as on a pulley. From the edge the external plates some small sharp spikes stand but their number and bulk are uncertain—To another pair may be added, to wit, the little riangular thin process, which comes from each side •f the body of the sphenoid bone, where the pterygoid rocesses are rising from it, and are extended over the j >wer part of the aperture of the sinus as far as to join be ethmoid bone, while their body hangs down into 1 e nares (a).—Besides these pairs of processes, there a sharp ridge which stands out from the middle of > base. Because it wants a fellow, it may be called rocessus azygos. The lower part of this process, i? here it is received into the vomer, is thick, and often ot quite perpendicular, but inclining more to one (I de than the other. The fore part of this process, i here it joins the nasal plate of the os ethmoides, is t iin and straight. These two parts have been de- iribed as two distinct processes by some. The depressions, sinuosities, and fossae, on the ex- Depres- ‘rnal surface of this sphenoid bone, may be reckoned sions. p to a great number, viz. two on the temporal apo- hyses where the crotaphite muscles lodge. Two on * Naviculares. f Lateral. E. + Mesial. E. acad.(a) Albin.des sciences, Tab. oss.1744.—Sue, 5. fig. 2. planche 6. A. A—Bertin.viii. fig. 2, 3, Mem. 4, 5, 6.de E 5 I OF THE SKELETON. the orbitar processes, to make way for the globes .. the eyes.—Two betw’een the temporal and spina .1 processes, for receiving the temporal bones.—Two b tween the plates of the pterygoid processes, where ti j. musculi pterygoidei interni and ptery-staphylini inter .. are placed.—Two between the pterygoid and orbit - processes, for forming the holes common to this and .. the cheek and maxillary bones.—Two on the low c ends of the aliform processes, into which the pale bones enter.—Two at the roots of the temporal ai pterygoidternal pterygoid processes, muscles where have the theirlargest rise—Two share of the at et .. sides of the processus azygos, for forming part of t nose, &c. Surface.Internal spinousWhat processes I described on theunder outside the nameof the of skull, temporal are lik ai -t wise seen on its inside, where they are concave, 1 receiving part of the brain, and commonly only thr . apophyses on the internal surface of the sphenoid bo . are mentioned. Two rising broad from the fore-ps , of its body, become smaller as they are extended a j liquely backwards. The third, standing on a loi |' transversethis bone, risesbase, nearlynear theerect, back-part and of an of equal the bread!body terminating often in a little knob on each side. Ti three are called clinoid, from some resemblance whi [ they were thought to have to the supporters of a be . ■ Sometimes one or both the anterior clinoid process are joined to the sides of the posterior one, or the bo* t of the bone itself.—From the roots of the anterii . clinoid processes, the bone is extended on each si> . outwards and forwards, till it ends in a sharp poim which may have the name of the transverse spino processes. Between, but a little farther back thi the two anterior cUnoid processes, we see a protub t ranee considerably smaller than the posterior dim ; process, but of its shape. Another process from b tween the transverse processes, often forces itself fo] wards into the os ethmoides. Within the skull, there are two sinuosities in tl. 1 internal part of each wing of the sphenoid bone, for r< THE SKELETON. 83 ceiving the middle part of the brain ; one between the transverse spinous processes, for lodging the part of the brain where the crura medulla oblongata are. Immediately before the third or middle clinoid pro- cess, a single pit may generally be remarked, from which a Jbssa goes out on each side to the holes through which the optic nerves pass. The pit is formed by the conjoined optic nerves; and in the fos- sa these nerves are lodged, as they run divided within the skull. Between that third protuberance and the tosterior clinoid process, the larger pit for the glandu- d pituitaria may be remarked. This cavity, because of its resemblance to a Turkish saddle, is always de- scribed under the name of sella Turcica or ephippium. On the sides of the posterior clinoid process a. fossa may be remarked, that stretches upwards, then is con- tinued forwards along the sides of the sella Turcica, near to the anterior clinoid processes, where a pit on each side is made. These Jossa point out the course of the two internal carotid arteries, after they have en- tered the skull.—Besides all these, several other fossa may be observed, leading to the several holes, and im- printed by the nerves and blood-vessels. The holes on each side of the os sphenoides are six Foramina. nroper, and three common—The frst is the round lole immediately below the anterior clinoid processes, for the passage of the optic nerve, and of the branch of the internal carotid artery that is sent to the eye.— The second is the foramen lacerum, or large slit be- :; tween the transverse spinous and orbitar processes; theextended interior outwards * end of t, whichit becomes slit isnarrower. large; and,The as outer it is end of it is formed in the os frontis ; and therefore this » might be reckoned among the common foramina.— Through it the third, fourth, the first branch of the fifth, and the greater share of the sixth pair of nerves, and an artery from the internal carotid, go into the orbit. Sometimes a small branch of the external caro- tid enters near its end, to be distributed to the dura * Mesial. E. 84 OF THE SKELETON. maier (a), and a vein, called by some the venous duct, or Nuck’s aquceduct, returns through it to the caver- nous sinus.—The third hole, situated a little below »- that just now described, is called rotundum, from its b shape. It allows passage to the second branch of the l fifth pair of nerves, or superior maxillary nerve, intc bn the bottom of the orbit. Thefourth is thefor amen ovale., fek about half an inch behind the round hole. Through b it the third branch of the fifth pair, or inferior maxil- !r t lary nerve, goes out; and sometimes a vein from the w dura mater passes out here (b).—Very near the point t". of the spinous process is the fifth hole of this bone. It is small and round, for a passage to the largest artery m of the dura mater, which is often accompanied with a a vein.—The sixth proper hole (c) cannot be well seen, i till the cuneiform bone is separated from all the othei » bones of the cranium; for one end of it is hid by a n) f, small protuberance of the internal plate of the ptery- s gold process, and by the point of the processus petro- 1 sus of the temporal bone. Its canal is extended above !«• the inner plate of the pterygoid process; and where it it opens into the cavity of the nose, it is concealed by r the thin luminous part of the palate bone. Through il if a considerable branch of the second branch of thejiftk % pair of nerves is reflected. Often in the middle of the ire sella Turcica a small hole or two pierce as far as the if cellular substance of the bone ; and sometimes at the (' sides of this sella, one or more small holes penetrate v into the sphenoidal sinuses. These observations af- u forded some anatomists (d) an argument of weight in i their days in defence of Galen (e), who asserted the s descent of the pituita that way into the sinuses below, fc Thsjirst of the common holes is that unequal fissure b (a) Winslow, Exposition anatomique du corps humain, train! >. desS arteres, Ingrass. § GO.Cammentar. et de la tete, in Galen, § 2G. de ossib. lib. I. comment. 8. 16. VidusVesal. Vidius, Anat. lib.Anat. 1. cap.lib. 2.12. cap. Eustach. 2. explicat. tab. tab.46. fig.5. and13. tab.and ?‘S' 5. (d)fig. Jac.8, 9, Svlv.10, lit. Calumni® O. secunds amolitio. Laurent. Hist, tit anat.(e) lib.Galen. 2. qusest.De usu 11. part. lib. 9. cap. 1. OF THE SKELETON. 85 ; at the side of the sella Turcica, between the extreme point of the os petrosum and the spinous process of the cuneiform bone. This hole appears only after the bones are boiled; for in a recent subject its back part is covered by a thin bony plate that lies over the in- ternal carotid artery, and further forward it is filled with a cartilaginous ligament, under which the carti- laginous part of the Eustachian tube is placed: It was by this passage that the ancients believed the slimy ^matter was conveyed from the emunctory of the , brain, the glandula pituitaria, to the fauces. The se- I land common hole is the large discontinuation of the a external * side of the orbit, left between the orbitar irocesses of the cuneiform bone, the os maxillare, ma- ce, and palati. In this large hole the fat for lubricating ti ihe globe of the eye and temporal muscle is lodged, i and branches of the superior maxillary nerve, with J small arteries from the carotid and veins pass. The =i'.hird the root hole of is theformed orbitar between process the of base the of palate this bone bone and of . ;ach side. Through this a branch of the external ca- i y "otid artery, and of the second branch of the fifth pair ; )£ nerves, are allowed a passage to the nostrils, and a . 'eturning vein accompanies them. Sometimes, how- i wer, this hole is proper to the palate-bone, being en- irely formed out of its substance. Under the sella Turcica, and some way farther for- . i yard, but within the substance of the sphenoid bone, !) ire two sinuses, separated by a bony plate. Each of hem is lined with a membrane, and opens into the : i ipper and back part of each nostril byjupund hole, . vhich is at their upper fore part. This nole is not brmed only by the os sphenoides, which has an aper- ure nearly as large as any transverse section of the inus, but also by the palate bones which are applied o the fore part of these sinuses, and close them up, • hat hole only excepted, which was already mention- id. Frequently the two sinuses are of unequal dimen- ions, and sometimes there is only one large cavity, . I nth an opening into one nostril. These cavities are Lateral. E. 86 OF THE SKELETON. likewise said (a) to be extended sometimes as far bac c as the great foramen of the occipital bone. In oth( : subjects they are not to be found, when the bone : .«•'] composed of" large cells (ft). Some (c) mention a ci vity within the partition of the sinuses ; but it is smal The sphenoidal sinuses serve the same uses as tl Substance. frontal.As this bone is extremely ragged and unequal, s i . its substance is of very different thickness, being i some places diaphanous; in others it is of a middur k thickness, and its middle back-part surpasses tl Connexion. greatestThe os share sphenoides of the iscranium joined, inby thickness. its wings, to the p> ' rietal bones above, to the osfrontis and ossa malaru t before, to the temporal bones behind; by the fo: • part of its body and spinous processes, to the front *• and ethmoid bones; by its back-part, behind the tv sinuses, to the occipital, where it looks like a bone wit * the epiphyses taken off, and, as was formerly observi • in the description of the occipital bone, it cannot 1 i separated without violence in adults;—to the pala i bones, by the ends of the pterygoid processes, and sti - more by the fore-part of the internal plates of thepf [ rygoid processes, and of the sinuses;—to the maxt Hair lary bones, by the fore-part of the external pterygo j-v plates; to the vomer and nasal plate of the os ethmc des, by the processus azygos. All these conjunction in except the last, which is a schindylesis, are said to 1 i by the suture proper to this bone; though it is i t. first sight evident, that several other sutures, as tl transverse, ethmoidal, &c. are confounded with it. We see now how this bone is joined to all the bon of the cranium, and to most of the upper-jaw: ai > therefore obtained the name of the wedge-like-bone. if; The uses are so blended with the description, as u leave nothing new to be added concerning them. birth.State at of Thenine months;sphenoidal only bone the is great almost alee complete separate in after a fash m > (c)(a) Id.Albin. ibid. de ossib. § 39. (6) Vesal. lib. ]. cap. 6. THE SKELETON. 87 ,, ceration from the body of the bone.—The processus j azygos is very large and hollow;—the thin triangu- lar processes are not ossified;—the internal surface 1 of the body is unequal and porous;—the sinuses do not appear. Whoever is acquainted with each bone of the cra- nium, can, without difficulty, examine them as they i stand united, so as to know the shapes, sizes, distances, ■ &c. of their several parts, and the forms, capacities, &c. of the cavities formed by them, which is of great use towards understanding the anatomy of the parts contiguous to, contained within, or connected to them. Such a review is necessary, after considering each class of bones. Thus the orbits, nostrils, mouth, face, head, spine, thorax, pelvis, trunk, extremities, and skeleton, ought likewise to be examined (a). The Face is the irregular pile of bones, composing the fore and under part of the head, which is divided, by authors, into the upper and lower maxillce or jaws. The superior maxilla * is the common designation given to the upper immoveable share of the face ; Upper jaw. though, if we would follow Celsus (b), we should ap- ply the word maxilla to the lower jaw only, and the name mala to this upper jaw. In complaisance to prevailing custom, I shall, however, use the terms as now commonly employed. The shape of the superior jaw cannot easily be expressed; nor is it necessary, provided the shape and situation of all the bones nvhich compose it are described. It is bounded above by the transverse suture, behind by the fore part of the sphenoid bone, and below by the mouth, j | The upper jaw consists of six bones on each side, , jf a thirteenth bone which has no fellow, placed in Component the middle, and of sixteen teeth. The thirteen bones bones. ! ire, two ossa nasi, two ossa unguis, two ossa malarum, -,wo ossa maxillaria,two ossa palati, two ossa spongiosa , hferiora, and the vomer. 1,3 (o) See Tabular views of the Bones of the Head, in the In- -roduction.* ttuyuv, yutt,E. mandibula. (6) Lib. 8. cap. 1. 88 OP THE SKELETON. position.Relative nose;The the ossa ossa nasi unguis are areplaced at the at internalthe upper * canthipart ofof th«thi itI orbits ; ossa mcdarum form the prominence of th> i cheeks ; ossa maxillaria form the side of the nose, witi it - the whole lower and fore part of the upper jaw, an< the greatest share of the roof of the mouth : ossa •palat i are situated at the back part of the palate, nostrils it and orbit; ossa spongiosa are seen in the lower par | H of the nares; and the vomer helps to separate thes sr< Connexion. twoThe cavities. bones of the upper jaw are joined to the bone fill* of the skull by the schindylesis and sutures alread; described as common to the cranium and face, am ti. they are connected to each other by gomphosis am |k fifteen sutures. The gomphosis is only where the teeth are fixed ii d their sockets, and the schindylesis is only where th j edges of the vomer are joined to other bones. Sutures. bers,The which sutures have are been generally differently distinguished applied; and by therenum b-i • fore I join those (a) who prefer giving names t h ; each, which may be easily contrived from their situai v tion, or from the bones which they connect. The first is the anterior nasal f, which is straight is*! and placed longitudinally in the middle fore part 01 i the nose. e The second and third are the lateral nasal X, whicl in5 are at each side of the nose, and almost parallel to th' if first suture. Each of the two lacrymal is almost semi-circular n and is placed round the lacrymal groove. The sixth and seventh are the internal orbitar ; eacl Ir of which is extended obliquely from the middle of th J lower side of an orbit to the edge of its base. The two external orbitars are contained, each fron > * Mesial. E. —Rolflnc.(a) Vander Anat. Linden. 11b. 2.Medicin. cap. 25.—Schenk. physiolog. cap. Schel. 13. art.part. 2. §§ ull1C • part.+ Nasalis2. cap. 5.recta. £ Nasalis obliqua. OP THE SKELETON. ;he end of the internal orbitar, to the under and fore jart of the cheek. The tenth is the mystachial, which reaches only i rom the lower part of the septum narium to between i|.he two middle dentes incisores. The longitudinal palate * suture stretches from the : niddle of the foremost teeth through the middle of 11 the palate. The transverse palate one t runs across the palate, i .earer the back than the fore part of it. \ Each of the two palato-maxillary is at the back part ii f the side of each nostril. I The fifteenth is the spinous, which is in the middle i f the lower part of the nostrils. This may perhaps Iather thought a double schindylesis. 'he connexion of the ossa spongioso to the side of i nostril, is so much by a membrane in young sub- s, by a sort of hook, and afterwards by concretion inion of substance in adults, that I did not know 1 how to rank it; but if any chuse to call it a su- i, the addition of two transverse nasal sutures may nade to those above named. 'hese sutures of the face (formerly called harmo- ) have not such conspicuous indentations as those of skull; the bones here not having substance enough forming large indentations, and there being less ! acessity for security against external injuries, or any ; temal protruding force than in the cranium.— j hese sutures often disappear in old people, by the mes running into each other; which can do little j 'ejudice, because the principal use of the bones be- ■ g so numerous here, is to allow them to be extend- .. into a proper form. It is evident, from the manner of the conjunction these bones, that they can have no motion, except i ^ common with the cranium. The purposes which this pile of bones serves, will shewn in the description which I am to give of ich of them. Laquearis, palataria recta. f Arcuata, palatina postica. 90 OF THE SKELETON. Nasal Ossa Nasi, so named from their situation at t : root of the nose, are each of an irregular oblong squa i\ figure, being broadest at their lower end, narrowest » little higher than their middle, and becoming som what larger at the top, where they are ragged a: thickest, and have a curvature forwards, that tin .. connexion with the frontal bone might be strong* s —These bones are convex externally, and there! la ■ better resist any violence from without; and they a concave internally, for enlarging the cavity of the nos tie The lower edge of these bones is unequal, and iu stretched outwards and backwards, to join the car* * lages of the nostrils—Their anterior side is thick, t i. pecially above, and unequal, that their conjunction e each other might be stronger; and a small rising m u be remarked on their inner edge, where they are su fe tained by the septum narium.—Their posterior side, a its upper half, has externally a depression, is overla t ped some way by the maxillary bones, while its low |,v half covers these bones; by which contrivance, tin • do not yield easily to pressure applied to their for i* part or sides. A small hole is frequently to be observed on the external surface, into which two, three, or four holt uti which appear internally, terminate for the transmi H sion of small veins; sometimes the holes go no fu >« ther than the cancelli of the bones. The nasal bones are firm and solid, with very fe t cells or cancelli in them ; the thin substance of whi* (i they consist not requiring much marrow. They are joined above to the frontal bone, by t. i illarymiddle bones, of the bytransverse the lateral suture;—behind, nasal sutures;—below, to the ma tv>* the cartilages of the nose ;—before, to each other, 1 ft the anterior nasal suture;—internally, to the septu i< narium. These bones serve to cover and defend the root t the nose. In an infant the nasal bones are proportional > shorter, and less thick in their upper part than in £ adult, but are otherwise complete. Bones.Lacrymal Ossa Unguis, or Lacrymalia, are so named, b OF THE SKELETON. 91 ij cause their figure and magnitude are something near i to those of a nail of one’s finger, and because the tears .] pass upon them into the nose. Their external * surface is composed of two smooth concavities and a middle ridge.—The depression be- i hind forms a small share of the orbit for the eye-ball : to move on, and the one before is a deep perpendicu- ! lar canal, or fossa, larger above than below, contain- i ing part of the lacrymai sac and duct. This is the part that ought to be pierced in the great operation for the , fistula lacrymalis. This fossa of the hone is cribriform, j or has a great number of small holes through it, that \ the filaments from the membrane which lines it, in- ,.i sinuating themselves into these holes, might prevent a separation of the membrane, and secure the bone in • its natural situation.—The ridge between these two (cavities of the os unguis is the proper boundary of the orbit at its internal canthus ; and beyond which sur- l*. operationsgeons should here.—The not proceed internal backwards t or posterior in performing surface i of this bone consists of a furrow in the middle of two xmvexities. | The substance of the os unguis is as thin as paper, < ind very brittle ; which is the reason that these bones ire often wanting in skeletons, and need little force . j■ ;o pierce them in living subjects. Each of these bones is joined, above, to the Jrontal i )one, by part of the transverse suture ;—behind, to | he os planum of the ethmoid bone, by the same suture; , -r-before, and below, to the maxillary bone by the j acrymal suture.—Internally, the ossa unguis cover ome of the sinus etkmoidales; nay, are really continu- ius with the bony lam dice which make up the sides f these cells; so that they are as much part of the i ■thmoid bone as the ossa plana. These unguiform bones compose the anterior inter- al parts of the orbits, lodge a share of the lacrymai ac and duct, and cover the ethmoid cells—Their situ- ition and tender substance make a rash operator in : anger of destroying a considerable share of the or- ; an of smelling, when he is performing the operation * Lateral. E. + Mesial. E, OF THE SKELETON. for the Jistula lacrymnlis ; but when these bones are hurt, they cast off without much difficulty, and con- if sequently the wound is soon cured, unless the patienl v labours under a general cacoethes, or there be a pre. ;• disposition in the bones to caries; in which case a r large train of bad symptoms follows, or, at best, the i cure proves tedious. These bones are fully formed in a new-born child. ' Bones.Malar Ossa lreadyMalarum remarked, * was to the all name the upper given jaw; by Celsus.but i; |is1 asnow was appropriated a to the prominent square bones whicl a form the cheek on each side.—Before, their surface i: :• convex and smooth; backwards, it is unequal and con- k cave, for lodging part of the crotaphite muscles. The four angles of each of these bones have beer |j reckoned processes by some.—The one at the exter- nal cathus of the orbit, called the superior orbitar pro- fc- cess, is the longest and thickest. The second termi- J. nates near the middle of the lower edge of the orbi’ . in a sharp point, and is named the inferior orbitar pro-1 cess. The third, placed near the lower part of the k cheek, and thence called maxillary, is the shortest, anc i nearest to a right angle. The fourth, which is callec k zygomatic, because it is extended backwards to the zy p. goma of the temporal bone, ends in a point, and ha; i . one side straight, and the other sloping. Betweei ^ the two orbitar angles there is a concave arch, whicl ! makes about a third of the external circumference o r the orbit, from which a fifth process is extended back wards within the orbit, to form nearly one-third a ,, that cavity; and hence it may be called the interna >. orbitar process. From the lower edge of each of th* , ossa malarum, which is between the maxillary ane , . zygomatic processes, the masseter muscle takes it origin ; and from the exterior part of the zygomati .. process, the musculus distortor oris f rises; in bot] i which places the surface of the bone is rough. On the external surface of each cheek-bone, one o i more small holes are commonly found, for the trans t* ZygomaticusJugalia vel zygomatica, major. Alb. hypopia, E. subocularia. OF THE SKELETON. 93 ! mission of small nerves or blood-vessels, from, and ii sometimes into the orbit. On the internal surface are i the holes for the passage of the nutritious vessels of i these bones. A notch on the outside of the internal i orbitar process of each of these bones assists in form- tl■ ing the great slit common to this bone £nd to the I sphenoid, maxillary, and palate bones. The substance of these bones is, in proportion to j their bulk, thick, hard, and solid, with some cancelli. Each of the ossa malarum is joined, by its superior : and internal orbitar processes, to the os frontis and to i the orbitar process of the sphenoid bone, by the trans- il verse suture.—By the edge between the internal and i inferior orbitar processes, to the maxillary bone, by ,i the internal orbitar suture. By the side between the ) maxillary and inferior orbitar processes, again to the i? maxillary bone, by the external orbitar suture. By ij the zygomatic process, to the os temporum, by the t, zygomatic suture. i The cheek bones are entire, and fully ossified in all >"> their parts in infants. Ossa Maxillaria Superiora*, are the largest Superior 4 aones, and constitute the far greater part of the up- BonesMaxillary ! per jaw, which has appropriated the name of maxiU - I (aria to them. The figure of one of them, or of the l ;wo when joined, is so irregular, that words can scarcely give an idea of it. i The processes of each os maxillare may be reckoned Processes. 1 even.—The first is the long nasal one at its upper and ore part, which is broad below, and turns smaller, as il t rises upwards, to make the side of the nose. At the i oot of this, a transverse ridge may be observed with- j n the nostrils, which supports the fore part of the up- >er edge of the os spongiosum inferius. The second is .fit troduced backwards and outwards, from the root of he nasal process, to form the lower side of the orbit; nd therefore may be called orbitar. The edge of this : nrbitar process, and the ridge of the nasal one, which J s continued from it, make a considerable portion of he external circumference of the orbit. From the * Maxillse coronales, Barcl. Muscular Motions, p.174. 94 OP THE SKELETON. proper orbitar process, a very rough triangular sur. 1 face is extended downwards and outwards to be con. : 1 nected to the cheek bone ; and therefore may b< f- called the malar process, from the lowest protube- rant part of which some share of the massetei ' muscle takes its rise—Behind the orbitar process, s large tuberosity or bulge of the bone appears, whicl ' > is esteemed thefourth process. On the internal pari I* ! of this we often meet with a ridge, almost of the sam« P*ll height with that in the nasal process, which runs le '' transversely, and is covered by a similar ridge of thi palate bone, on which the back part of the upper edg< * of the os spongiosum inferius rests. The convex back- part of this tuberosity is rough, for the origin of par t*: of the external pterygoid muscle (a), and more inter- * t nally is scabrous, where the palate and sphenoid bones I*! are joined to it.—That spongy protuberance * at th< lower circumference of this bone, where the sockets te for the teeth are formed, is reckoned the Jifth—Tin t;. sixth is the horizontal plate, which forms the greatei -i part of the base of the nostrils, and roof of the mouth fee its upper surface, which belongs to the nostrils, is - very smooth, but the other below is arched and rough for the stronger adhesion of the membrane of the 1; mouth, which is stretched upon it, and in chewing speaking, &c. might otherwise be liable to be sepa- ^li! rated.—The seventh rises like a spine from the innei 6 .' edge of the last, and forms a small part of the parti- » tion of the nostrils. The depressions in each maxillary bone are, 1. A sinuosity behind the orbitar process, made by the '1 temporal muscle. 2. A pit immediately before the " same process, where the origin of the musculus eleva- u tor labiorum communisand elevator labii superior is, with a branch of the fifth pair of nerves, are lodged ^ securely. 3. The hollow arch of the palate. 4. The til. simicircular great notch, or entry to the lower part ■ of the nostrils, betwixt the root of the nasal process ’ and spine of the palate-plate.—Below this, the fore- part of the bone is flatted, or sometimes hollowed by ’ f(a) Lavator Albin. deanguli ossib. oris. § 79-Alb. E. OF THE SKELETON. 95 lie musculus depressor labii superioris *. 5. Sockets )r the teeth f: The number of these sockets is un- srtain; for the same number of teeth is not in all peo- le, and the four backmost teeth of each side of each iw vary greatly in their number of roots; and when le teeth of a living person fall out, or are taken vay, the sockets fill up with an osseous net-work, hich becomes solid afterwards. 6. The lacrymal *ssa in the nasal process, which assists the os unguis form a passage for the lacrymal duct. This part of . ie bone forming this fossa is so firm and strong, that i surgeon can scarcely perforate it with the ordinary struments for the jistida lacrymalis, and therefore , ight to avoid it in doing this operation —Immediate- on the outside of this, there is a small depression, i am which the inferior or lesser oblique muscles of the ' e has its origin (a). 7- The canal on the upper part ' the great tuberosity within the orbit, which is al- ost a complete hole: in this a branch of the superior : ixillary nerve passes.—Besides these, the superior j: rfaceider part of theof the great eye.—Immediately bulge is concave, above to receive the trans- the rse ridge in the nasal process, a small hollow is -med by the os spongiosum—In some subjects, the sal process has a small round pit above the lacrymal . ct, where the little tendon or ligament of the orbi- ; lar muscle of the eye-lids is inserted. It is this idon, and not the tendon of the larger oblique mus- of the eye, which there is some hazard of cutting ,, the operation for the fistula lacrymalis. The holes of this bone are two proper and two com- Fwaminm. j n, which are always to be found, besides several lers, whose magnitude, numbers, &c. are uncer- n.—The first of the proper is the external orbitar, ^mediately below the orbit, by which the infra- ; litar branch of the second branch of the fifth pair of •ves, and a small artery, come out, after having ,sed in the canal, at the bottom of the orbit, de- , « • DepressorBaJjia, tXpirxM, al* nasi. alveoli, Alb. fossulae,E. mortareola, frsena, looelli, e,») prasepiola,Winslow, Expositionloculamenta. Anatomique des os secs. § 276. I 96 OF THE SKELETON. scribed numb. 7- of the depressions—This hole is ofl double, and that when the nerve has happened to sj iF before it has escaped from the bone.—The second the foramen incisivum, just behind the fore-tee ;, which, at its under part, is one irregular hole comm « to both the maxillary bones when they are joine but, as it ascends, soon divides into two, three, . sometimes more holes; some of which open into ea , nostril. Through them small arteries and veins, a , a twig of the second branch of the fifth pair of nen [. fjass, and make a communication between, or join t ],. ining coats of the nose and mouth. In some su . jects, Sleno's duct may be traced some way on the si of these passages next to the nose, and small orifk rf may be observed opening into the mouth. The first common hole is that which appears at t inner side of the back part of the luberosily and of t sockets of the teeth, and is formed by a fossa in tl bone, and a corresponding one in the os palati; throu it a nerve, which is a branch of the second branch , the fifth pair, runs to the palate.—The other comm ► hole is the great slit in the outside of the orbit c ’ scribed already, as the second common hole of t, sphenoid bone. On the nasal process, holes may be often observ . for the passage of vessels to the substance of the bone ", and, at the back part of each tuberosity, several /or ' mina are placed, for the transmission of nerves to t cavity within ; but these are uncertain. All the body of the maxillary bone is hollow, a: Antrum leaves a large sinus like the frontal and sphenoi i Highmo- which is commonly, but unjustly, called antrum Hig morianum *. When the os maxillare is single or sep rated from all the other bones of a skeleton, its antn appears to have a large aperture into the nostril but, in a recent subject, it is so covered at its ba part, by the palate bone; in the middle, by the i spongiosum inferius-, before, by a strong membran' that only one, or sometimes two holes, scarcely larg than a crow-quill, are left at the upper part; whic after a short winding progress, open into the nostri t * Genae. OF THE SKELETON. 97 jetween the two ossa spongiosa.—Kt the bottom of his cavity, we may often observe some protuberances, n which the small points of the roots of the teeth are :ontained (a).—This cavern and the sockets of the eeth are often divided by the interposition only of a erv thin bony plate, which is liable to be eroded by crid matter collected in the antrum, or to be broken t i drawing a tooth (6). The symptoms of a collec- i ion of matter here naturally lead us to the practice f pulling out the teeth, and piercing through this < late into the antrum, to procure an evacuation of the i ollected matter; by which considerable service is •;! -equently done (c). | The maxillary sinuses have the same uses as the ! ontal 'xnA. sphenoidal; and the situation of the sinu- •s is such, that the liquor trickling from them, from le cells of the ethmoid and palate bones, and from le lacrymal ducts, may always moisten all the parts i the membrane of the nares in the different situa- ms in which the head is placed. Though the membranes which line the frontal, Membrane »' henoidal, and maxillary sinuses, are continuations of of the at which covers the bones within the nose ; yet Sinuses, ey are much thinner than it is, and have so much 1 laller vessels, that the injection which makes the embrane of the nose red all over, fills only some few - sselsofthe maxillary sinuses, and is scarcely obser- - | d in the frontal and sphenoidal. Are not the larger ssels intended for a more plentiful secretion of a i • icid liquor to defend the membrane from the effects the perfatus, which is constantly passing through u ■ ; nose ? Are not the membranes which have the allest vessels, cceteris paribus, the most sensible? • " e not many phenomena of smelling, inflammations ■ these parts, megrim, polypi, &c. depending on this ucture of these membranes ? The substance of the ossa maxillaria is compact and Substance. vjj i)a) Highmore,Highmore, ibid.Disquis. Anat. lib. 3. part 2. cap. 1. ', c)iays Cooper and Obs. in Drake’svol. 5. art. anthropol. 30. book 3. chap. 10.—Medical OF THE SKELETON. firm, except at the inferior processes, in which tl teeth are lodged, where it is very spongy. Connexion. endsThe of maxillary their nasal bones processes are joined to the above osfrontis, by the byupp tl :: transverse suture ;—at the sides of these processes the ossa unguis, by the lacrymal sutures;—to the n v sal bones, by the lateral nasal sutures;—by their c bitar processes, to the cheek bones, by the external c [' bitar sutures;—by the internal sides of the interr p orbitar processes, to the ossa plana, by part of t J* ethmoidal suture;—by the back part of the tubero p ties to the palate bones, by the suturce palato ma illares by the posterior edges of their palati lamellce, to the ossa palati, by the transverse pals suture;—by their nasal spines, to the vomer, by t spinous suture;—by their sockets, to the teeth ’ “ gomphosis ;—hy the internal edge of the palate-pla 1* ■' to each other, by the longitudinal palate-suture ; the upper and fore part of which a furrow is left i J receiving the cartilage which forms the partition • the nostrils ; between the fore part of the nostrils a mouth, to each other, by the mystachial suture; S sometimes they are connected to the ossa spongic p inferiora, by a plain concretion or union of substam P Uses. These bones form the greater part of the nose a - of the roof of the mouth, and a considerable share ^ the orbit. They contain sixteen teeth, give rise " muscles, transmission to nerves, &c. as mentioned the description of their several parts. Birth.State at theIn external each of orbitar the maxillary process bonesis hollow, of a with new-born remarkal chi P'• holes in it;—there are five sockets for the teeth, which the two posterior are very large, and when i P vided by a second cross partition, make the numt of sockets six (a). The palate-plate is cribrifo: ‘ about the middle. The great tuberosity is not for: 1 ed;—instead of the antrum, there is only an oblo depression at the side of the nostrils. Bones.Palate squareOssa bones, Palati at theare backcommonly part of described the palate as twoor roof sm: . secundjun.(a) Albin. §Osteogen, ]. tab. 5. fig. 45. Ungebav. de dent OF THE SKELETON. the mouth, though they are of much greater extent, being continued up the back part of the nostrils to the orbit (a). Each palate bone may therefore be di- vided into four parts; the palate square bone, the pte- rygoid process, nasal lamella, and orbitar process. The square bone is unequally concave, for enlarg- Their both the mouth and cavity of the nose. The up- Square pero part of its internal* edge rises in a spine, after Bone, the same manner as the palate-plate of the maxillary bone does, to be joined with the vomer. Its anterior idge is unequally ragged, for its firmer connexion with die palate process of the os maxillare. The internal ;dge is thicker than the rest, and of an unequal sur- ace, for its conjunction with its fellow of the other ide. Behind this bone is somewhat in form of a cres- ent, and thick, for the firm connexion of the velum pendulum palati; the internal point being produced tackwards, to afford origin to the palato-staphylinus or ’"'•gos muscle. This square bone is well distinguish- from the pterygoid process by a perpendicular Jbs- which, applied to such another in the maxillary one, forms a passage for the palatine branch of the fth pair of nerves; and by another small hole behind his, through which a twig of the same nerve passes. The pterygoid process is somewhat triangular, hav- Pterygoid ig a broad base, and ending smaller above. The Process, ack part of this process has three fossae formed in it; le two lateral receive the ends of the two plates of le sphenoid bone, that are commonly compared to a it’s wing; the middleyima makes up a part of what commonly called the fossa pterygoidea; the fore- ie of this palatine pterygoid process is an irregular ■ mcave, where it receives the back part of the great berosity of the maxillary bone. Frequently several aall holes may be observed in this triangular pre- ss, particularly one near the middle of its base, hich a little above communicates with the common d proper holes of this bone already taken notice of. Sl («) Eustach. tab. 47. fig- J. 3. 6, 7, 8. Vidus Vidius, de - nat.I’acad. lib. 2.des cap. sciences, 2. explicat. 1720. tab. 6. fig. 19.* MesialWinslow, edge. Memoires E. F 2 100 OF THE SKELETON. The nasal lamella of this bone is extremely thi NasalPlate. and brittle, and rises upwards from the upper side < the external edge of the square bone, and from th narrow extremity of the pterygoid process ; where is so weak, and, at the same time, so firmly fixed the maxillary bone, as to be very liable to be broke in separating the bones.—From the part where tl _ plate rises, it runs up broad on the inside of the tub* rosity of the maxillary bone, to form a considerab share of the sides of the maxillary sinus, and to clos up the space between the sphenoid and the gre: bulge of the maxillary bone, where there wou. otherwise be a large slit opening into the nostrils (a From the middle internal side of this thin plate, a cro ridge placed on such another of the maxillary bone extended; on it, the back part of the os spongiosu r~ inferius rests. Along the outside of this plate> tl perpendicular fossa made by the palate nerve, is o' ™ servable. Atit the upper part of this nasal plate, the pala ? Process.Orbitar bonee divides into two processes, which I have alreac 1 • named orbitar •, between which and the body of tl sphenoid bone, that hole is formed which I mention) as the last of the holes common to the sphenoid bon Sometimes this hole is only formed in the os pale by a cross plate going from the one orbitar process the other. A nerve, artery, and vein belonging the nostrils pass here. The anterior of the two orl tar processes is the larger, and has its fore part coni guous to the back part of the maxillary sinus, and i upper surface appears in the bottom* of the orbit, b hind the back part of the os maxillare and planum.- It has cells behind resembling those of the ethma bone, to which it is contiguous; it is placed on t aperture of the sinus sphenoidalis, so as to leave on a round hole at its upper fore part. The other pg of the orbitar process is extended along the interr side of the upper back part of the maxillary tuberosu to the base of the sphenoid bone, between the root " the process azygos and the pterygoidprocess, (o) Albin. de ossib. § 88. * Inial and trie),Basilar fpfttt- part. OP THE SKELETON. 101 The palate square part of this palate bone, and its Substance, pterygoid process, are firm and strong, with some can- celli; but the nasal plate and orbitar processes are very thin and brittle. The palate bones are joined to the maxillary, by the Connexion, re edge of the palate square bone, by the transverse palate suture: By their thin nasal plates, and part of their orbitar processes, to the same bones, by the pa- lato-maxillary sutures : by their pterygoid processes, and back part of the nasal plates, to the alae vesperti- lionum, by the sphenoid suture: By the transverse ridges of the nasal plates, to the ossa spongiosa infe- riora, by contact; hence frequently there is an inti- mate union of the substance of these bones in old skulls:—By the orbitar processes, to the ossa plana and cellulcB ethmoideae, by the ethmoid suture: To the body of the sphenoid bone, by the sphenoid su- lure: By the internal edge of the square bones, to jach other, by the longitudinal palate suture, and by their nasal spines, to the vomer by the spinous suture. The palate bones form part of the palate, nostrils. Uses, yrbits, and fossae pterygoideae, and they cover part of ;he sinus maxillares sphenoidales, and ethmoidei. These bones are very complete in a new-born in- state at ’ant, the nasal plates being then thicker and stronger Birth. ;han in adults; but the orbitar processes have not the sells which appear in the bones of adults. When we are acquainted with the history of these Jones, the reason is evident, why the eyes are so much iffected in ulcers of the palate, as to be often attended vith blindness, which frequently happens in an ill- nanaged lues venerea ; or why, on the other hand, the salate suffers from an aegylops (a). Ossa Turbinata, or spongiosa inferiora, resemble inferior he superior ossa spongiosa in shape and substance, spongy »ut have their anterior and upper edges contiguous to Bones, lihe transverse ridges of the maxillary and palate bones. 'rom their upper straight edge, two small processes tand out: the posterior, which is the broadest, de- ,toA the lower and back parts of the partition of the nose (e). a The figure of this bone is an irregular rhomboid.— - Its sides are flat and smooth. Its posterior edge ap- tv pears in an oblique direction at the back part of the v nostrils. The upper one is firmly united to the base of ) (a) Cowper in Drake’s Anthropolog. book 3. chap. 10. (A)(c) Santorin.Id. ibid. cap. Observat. 5. § 7- anatomic, cap. 5. § 9. fe)(d) Columb.Hunauld. de in re Memoiresanat. lib. 1. de cap. 1’acad. 8.—Fallop. des sciences, Observ. 1730. anatom. OP THE SKELETON. 103 ie sphenoid bone, and to the nasal plate of the eth- oid, and, when it can be got separated, is hollow, for sceiving the processus azygos of the sphenoid. The an- irior edge has a long furrow in it, where the middle irtilage of the nose enters. The lower edge is firmly mited to the nasal spines of the maxillary and palate mes. These edges of this bone are much thicker than r middle, which is as thin as the finest paper; by hich, and the firm union or connexion this bone has love and below, it can very seldom be separated entire adults; but, in a child, it is much more easily sepa- ated entire, and its structure is more distinctly seen; j therefore I shall examine all its parts of such a subject. Its situation is not always perpendicular, but often xclined and bended to one side, as well as the nasal ,i late of the ethmoid bone. The vomer is convex at its upper part, and then is j ;raight, as it is extended downwards and forwards .1 here it is composed of two plates; the edges of which ive a great number of small processes, disposed some- ... hat like the teeth of a saw, but more irregularly, and ) jveral of them are reflected back. Between these lates is left a deep fossa, which, as far as the top of le curvature, is wide, and has strong sides for receiv- . i ig the processus azygos of the sphenoid bone. Beyond . lie arch forwards, the fossa is narrower and shallower Gradually to the point of the bone, receiving for some lay the nasal lamella ethmoidea ; which, after the os- Jfication is complete, is so closely united to the vomer the little processes piercing into its substance, as to , -event any separation ; on which account it has been teemed by some (a) a part of the ethmoid bone. The iddle cartilage of the nose fills up what remains of ie fossa at its fore part. The posterior edge of the mer, which appears above the back part of the palate mes, is broader above; but as it descends forwards, icomes thinner, though it is still solid and firm. The wer edge of this bone, which rests on the nasal spine the palate and maxillary bones, has a little furrow (a) Lieutaud. Essais anatomiques, 1 sect. 1’os ethmoide. F 4 104 OF THE SKELETON. on each side of a small middle ridge, answering to tl spines of the hones of different sides, and the interstic n between them. This edge and the upper one meet i » the pointed fore end of this bone. The body of the vomer has a smooth surface, an solid, but thin substance; and towards its sides, whei W it is thickest, some cancelli may be observed, when tl i bone is broken. It is joined above to the sphenoid and ethmoid bone *, and to the middle cartilage of the nose, by schindyh ry sis;—below, to the maxillary and palate bones, t t the spinous suture. The vomer divides the nostrils, enlarges the orga i of smelling by allowing place for expanding the men brane of the nose on its sides, and sustains the palati .■ plates of the maxillary and palate bones, which othe: ) wise might be in hazard of being pressed into tl >. nostrils ; while the vomer is secured from shuffling t . one side or other by the double schindylesis, by whic * it is joined to the bones above and below. These then are all the bones which compose the uj f per j aw, except the teeth, which are so much a-kin t those of the lower jaw, that I choose to make one d« \ scription serve for both, in which the differences ol t servable in them shall be remarked, after the secon It» part of the face, the lower jaw, is examined; becauf y the structure of the teeth cannot be well understoo* y( until the case in which they are set is explained. t Maxilla.Inferior Maxillaveable Inferior*, bone, and sixteenthe lower teeth jaw incasedconsists intoonly i< » oneThis m0 bone, which is somewhat of the figure of tl r Greek letter a, is situated at the lower part of the fac m so that its convex middle part is forwards, and its leg; u are stretched back. It is commonly divided into th i chin, sides, and processes.—The chin is the midd! / fore part, the extent of which to each side is marked a the external surface by the holes observable there, an i internally by the beginning of an oblique ridge.—Bi l yond these the'Mrfes appear, and are continued till th Muse.* rtMf, Mot. naym, p. 16?. mandibula, E. facies. Maxilla basilaris. Bare OP THE SKELETON. 105 :i >ne, by bending upwards, begins to form the pre- sses. On the fore part of the chin, a transverse ridge ap- ! ars in the middle, on each side of which the musculi i i adrati, or depressores labii inferioris, and the levato- 11 labii inferioris*, depress the bone, and below these : ints, a small rising may be observed, where the de~ ,ri essores commence.—On the back part of the chin, j netimesthree,alwaystwo, small protuberancesappear i the middle. To the uppermost, when it is seen, the ! lenum of the tongue is connected. From the middle e, the musculi genioglossi rise; and from the lowest, ?! igeniohyoideihave their origin. Belowthe last, we see 0 rough sinuosities formed by the digastric muscles. i At the lower and fore part of the external surface Sides. each side of the lower jaw, a small eminence may i! observed, where the depressor lahiorum communis\ i es. Near the upper edge of the side a ridge runs gth-ways, to which the under part of the musculus reicinator of each is connected—Internally, side, appears another ridge, towards from the whichupper 1! mylohyoidei have their origin, and to which the in- nal membrane of the gums adheres. [n the upper edge of both chin and sides are a great Aloeoti. ny deep pits or sockets, for receiving the roots of : teeth. 1 he number and magnitude of these sock- are various, because of the different number, as 111 of the teeth themselves, as of their roots, in dif- ••n Bnt people. These sockets in this lower jaw, as well | in the upper one, are less deep as old age comes on ; en freed from the teeth by any means, they are :ie time after filled up with an osseous net-work, ich at last becomes entirely solid, and as smooth as other part of the bone; so that in a great many 1 jaws one cannot observe a vestige of the sockets : < t then the jaw becomes less, and much narrower (a). flence we may know why the chin and nose of mtulous people are much nearer than before the th were lost; while their lips either fall in towards * Levatores menti. Alb. E. +(a) Depressor Vesal. Anat. anguli lib. oris. 1. cap.Alb. 10, E. F 5 106 OF THE SKELETON. the mouth, or stand prominent forwards.—When u «£ teeth are protruded, new sockets are formed (a) - The lower edge of the chin and sides is smooth s ‘ equal, and is commonly called the base of the loi 1 jaw.—The ends of the base, where the jaw turns 1 " wards, are called its angles; the external surface I1! each of which has several inequalities upon it, wh N the masseter muscle is inserted; as the internal surf ^1 also has, where the pterygoideus internus is insert il and a ligament extended from the styloid process ' the temporal bone is fixed. 1 Processes. The processes are two on each side—The antei sharp thin caronoid ones have the crotaphite muscles Bit serted into them.—The posterior processes or condyl * terminate in an oblong smooth head, supported by a c t vix. The heads whose greatest length is transvei t andwhose convexity is turned forwards, are tipped W cartilage, as the articulated parts of all other mo\ S:< bones are. The fore part of the root and neck of tht c condyloid processes are a little hollow and rough, wh< 4 Foramina. theThe external holes pterygoidof the lower muscles jaw are inserted.two on each sid =1: one at the root of the processes internally, where 1 large branch of the third branch of the fifth pair 1: nerves enters with an artery, and a vein returns. : * small sharp process frequently juts out backwai Hr from the edge at the fore part of this hole, to whicl ligament extended from the temporal bone is fixed ( t which saves the nerve and vessels from being too mu ! pressed by the pterygoid muscles. From the low * side of this hole, either a small superficial canal oj •’ furrow descends, where a branch of the nerve is lod ed, in its way to the mylo-hyoideus muscle and subli te gual gland (c). The other hole is external, at the cc fines of the chin, where branches of the nerve al vessels come out. The canal betwixt these two holes « formed in the middle of the substance of the bone, ai is pierced by a great number of small holes, by whi t; the nerves and blood-vessels of the cancelli and teet t (a) Fallop. Observ. anat. (c)* Articulatorii. Palfyn. Anat. chirur.(6) Weitbrecht. traite 5. chap. Syndesmolog. C. fig. 32. '' or THE SKELETON. 107 ; )ass. This canal is continued a little further than the i xternal hole at the chin. On account of the vessels :! nd nerves in the lower jaw, fractures of it may be at- i ended with dangerous symptoms. | The surface of the lower jaw is hard and firm, ex-Substance. ; ept at the spongy sockets, where however it is stronger | han the upper jaw. Its internal substance is cellular, ' without any solid partition between the cancelli in its I riddle. At the base, especially of the chin, where | his bone is most exposed to injuries, the solid sides of i b are thick, compact, and hard. ! The lower jaw generally receives the roots of six- Connexion, [een teeth into its sockets, by gomphosis; and its con- yloid processes, covered with cartilage, are articulated : uth the temporal bones, in a manner that is not com- .. lonly described aright: For, as was already mentioned i the description of the temporal bones, not only the )re part of the cavity between the zygomatic, auditory, nd vaginal processes, but also the adjoining tubercle , L the root of the zygomatic process of each os tempo- utn is covered with a smooth cartilage, for this articu- ition.—Here also is placed an intermediate moveable , irtilage, which being thin in the middle, and thick . t the edges, is concave on both sides; and is connect- d so firmly by ligaments to each condyle, as to follow le motions of the condyle; and so loosely to the tem- i oral bone, as readily to change its situation from the ivity to the tubercle, and to return again ; while the . immon ligament of the articulation affords space rough for such a change of place backwards and for- ards; but, like other ligaments of the joints by ging- mus, is strong and short at the sides, to confine the v teral motions. ' When therefore the teeth of both jaws coincide, the Motions of mdyles are lodged securely in the temporal cavities, the lower j at their motions to either side must be confined both Jaw> y the firmness of the ligaments, and the rising brims diich are on each side of the cavities. When the jaw i brought directly forwards, the condyles and interme- iate cartilages descend and advance forwards upon the ubercles. In this situation the lateral motions are a ttle more free than in the former one, from the want F 6 108 OP THE SKELETON. of rising brims to stop the condyles. When the for« teeth of the lower jaw are moved forwards, and to r side, the condyle of the opposite side is either advai: . ced from the cavity of the tubercle, while the condy. of the same side remains in the cavity; or if both coi j; dyles are on the tubercles, when the jaw is moved ot if liquely to a side, the condyle of the side to which tb ;» motion is made slides back from the tubercle to th y cavity. When the mouth is opened by the descent c mj the lower jaw, the fore part of it, where the depressin muscles are fixed, is drawn backwards, as well t downwards, while resistance is made to the angle moving backwards by the masseter and internal fieri, gold muscles, and, at the same time, the externc Y' pterygoid draw the condyles and their moveable carti '( lages forwards; and therefore, when the mouth is oper » ed, the condyles are carried forwards upon the tuber i cles, and the axis of motion of the bone is a little abov i its angles. But in this situation there is less resistance than in any other, to the condyles luxating forwards (|t a disease which seldom happens, except when peopl ^ are gaping too wide; and therefore the common prac ?. tice of nurses, who support the jaw of infants whei ^ they are yawning, is reasonable. In chewing there i a succession of the motions above described (a). Here a general remark may be made. That where- ever moveable cartilages are found in joints, either th« articulated bones are of such a figure, or so joined anc , fixed by their ligaments, that little motion would be, allowed without such cartilages; or else some motion; ». are necessary to the right use of the member, whicl j- the form of the articulation would not otherwise allow This will more fully appear after the other joints wit! •■ such cartilages are described. Birth.State at composedIn a child of borntwo atbones, the fullconnected time, thein thelower middle jaw olis | i the chin by a thin cartilage, which gradually ossifies, jL; and the two bones intimately unite. In each of these Medical(a) For Essays a more and full observ.account vol. of this1. art.articulation, 11. andvol. vid. III. Edinburgh art. 13. /• —Works, Memoires 4to. p.de 231,1’acad. and des Barclay sciences, on Muse. 1744.—See Mot. 483. also Monro(r;E. * OF THE SKELETON. 109 bones there are five or six sockets for teeth, as in the upper jaw. After I have thus described the incasement of the Uses, teeth, the insertion of so many muscles of the tongue, ind of the os hyoides, the connection of the membrane >f the tongue to the maxillary bone, and the motions >f this bone, it is easy to see, that the lower jaw must je a principal instrument in manducation, deglutition, ind speech. The Teeth are the hard white bodies placed in the Teeth. i ockets of both jaws. Their number is generally six- : een above, and as many below; though some people •f■ lave more, others have fewer. i< The broad thick part of each tooth which appears Parts. 1 dthout the socket, is the base or body *. The smaller »t recesseshich become sunk graduallyinto the maxillae, smaller aretowards the roots the orend fangs, far- i rest from the base, or are nearly conical, by which 2 ie surface of their sides divides the pressure made on i te bases, to prevent the soft parts, which are at the . nail points of the sockets, from being hurt by such > t ressure. At the place where the base ends, and the i >ots begin, there is generally a small circular depres- K on, which some call the neck or collar. Without the gums the teeth are covered with no embrane, and they are said to have no proper pe- osteum, within the sockets, but that is supplied by ■t e reflected membrane of the gums; which, after a l od injection, may be evidently seen in a young sub- ; ;t, with the vessels from it penetrating into the sub- , ,ii othmce recently of the teeth pulled, ; and by itmacerating may he discovered it in water in (a),any ic adhesion of this membrane to these roots is ; engthened by the small furrows observable on them. : Each tooth is composed of its cortex, or enamel, and Composi- ; i internal bony substance. The cortex has no cavityt!on- ij place for marrow; and is so hard and solid, that saws files can with difficulty make impression on it. It is ckest upon the base, and gradually, as the roots turn aller, becomes thinner, but not proportionally to the jrerence of the size of the base and roots.—The fibres t. jhorona. (a) Cowper, -Anat. Explicat. tab. 92. fig. 7« lit. E. no OF THE SKELETON. ofstance, this enamel and are are straight all perpendicular on the base, tobut the at internalthe sides sub' art arched with a convex part towards the roots (a); whicl i makes the teeth resist the compression of any har< ... body between the jaws, with less danger of breaking i these fibres, than if they had been situated transverse ..f ly. The spongy sockets in which the teeth are placed likewise serve better to prevent such an injury, than : i. more solid base would have done. Notwithstanding th ; great hardness of this cortex, it is wasted by manduca ..... tion. Hence the sharp edges of some teeth are blunted . and made broad, while the rough surfaces of others ar rf made smooth and flat, as people advance in life. The bony part of the teeth has its fibres running | straight, according to the length of the teeth. Whei it is exposed to the air, by the breaking or falling ol t of the hard cortex, it soon corrupts. And thence ca r; rious teeth are often all hollow within, when a ven . small hole appears only externally. Canals. The teeth have canals formed in their middle j, wherein are lodged their nerves and blood-vessels X which they certainly need, being constantly wasted b , the attrition to which they are subjected in manduca , tion, and for their further growth, not only after the first appear, but even in adults ; as is evident when lr tooth is taken out: For then the opposite one become i*. longer, and those on each side of the empty sockets tur , broader; so that when the jaws are brought together, i . is scarcely observable where the tooth is wanting (b} VesselsNerves. and theThe large vessels canal, are but easily can scarcely traced sobe long observed as they in arethei i: J' distribution from that to the substance of the teeth t adults. Ruysch (c) however affirms, that, after injec l tion, he could trace the arteries into the hardest part c \ the teeth, and Leewenhoek (d) suspected the fibres c . the cortex to be vessels. In children I have frequentl injected the vessels of the teeth as far as their bas« : (a)(1) Ingras.Havers, de Osteolog. tumor, cap.nov. 1.disc. p. 24,1. 25, 26. (c)(d) Thesaur.Arcan. natur. 10. num. continual, 27- epist. p. 3. OF THE SKELETON. Ill and in such as are not entirely ossified, one can with ■ a lucky injection fill so many vessels, as to make both the outside and inside of the cortical part appear per- fectly red. This plentiful supply of vessels must ex- pose the teeth to the same disorders that attack other vascular parts; and such teeth as have the greatest number of vessels, must have the most numerous chances of being seized with these diseases. Every root of each tooth has such a distinct canal, t with vessels and nerves in it. These canals in the teeth, ' with more than one root, come nearer each other, as hey approach the base of the tooth ; and at last are separated only by very thin plates, which being gene- rally incomplete, allow a communication of all the Ca- lais ; and frequently only one common cavity appears . i within the base, in which a pulpy substance, composed >f nerves and vessels is lodged. The condition there- ore of the nerves here bears a strong analogy to that if the cutaneous nerves which serve for the sensation Ji if Thetouching. entry of the canals for these vessels is a small s! iole placed a little to a side of the extreme point of > ach root; sometimes, especially in old people, this is iole is entirely closed up, and consequently the nerves : i nd blood-vessels are destroyed (a). 11 The teeth are seen for a considerable time in form of Evolution. ■ -i mens contained in a membrane; afterwards a thin cor- ; * ical plate, and some few osseous layers appear within le membrane, with a large cavity filled with mucus in he middle; and gradually this exterior shell turns ts iiicker, the cavity decreases, the quantity of mucus is v ;ssened, and this induration proceeds till all the body is ! irnied; from which the roots are afterwards produced. t In young subjects, different stamina or rudiments of i jeth are to be observed. Those next the gums ordina- ilyr hinder the deeper-seated ones from making their ay out, while these prevent the former from sending nt roots, or from entering deep into the bony sock- :s of the jaws; by which they come to be less fixed. Children are seldom born with teeth; but usually at Changes, wo years of age they have twenty; and their number oes not increase till they are about seven years old, H (a) De la Hire, Histoire de 1’acad. des sciences 16.99. 1]2 OP THE SKELETON. when the teeth that first made their way through the n- gums are thrust out by others that have been formed t- deeper in the jaw, and some more of the teeth begin t( discover themselves farther back in the mouth. About < fourteen years of age, some more of the first crop are |. shed, and the number is increased. This shedding oi the teeth is of good use; for if the first had remained, r they would have stood at a great distance one from Li another ; because the teeth are too hard in their outei crust, to increase so fast as the jaws do. Whereas botl: wk. the second layer, and the teeth that come out late jf,i meeting, while they are soft, with a considerable re- r sistance to their growth in length, from those situated „ upon them, necessarily come out broad, and fit to make ■, that close guard to the mouth*, which they now form Connexion. andThe the teeth gums are contribute joined toto thefix themsockets there by ;gomphosis. as is evi- if, dent by the teeth falling out when the gums are any ;, Way destroyed, or made too spongy ; as in the scurvy t or salivations : whence some (a) class this articulation f Uses. withThe the uses syssarcosis. of the teeth are to masticate our aliment >*- and to assist us in the pronunciation of several letters || Differences. Though the teeth so far agree in their structure. * T > ^ yet, because of some things wherein they differ, they h are generally divided into three classes, viz. incisores: ir canini, and molaresy Jndsores. receivingThe incisores their name| are fromthe four their fore office teeth of incutting each jaw,oui ... aliment; for which they are excellently adapted, be- f. ing each formed into a sharp-cutting edge at theii . base, by their fore side turning inwards there, while r they are sloped down and hollowed behind f; so that - they have the form of wedges; and therefore their power of acting must be considerably increased— ,r Seeing in the action of the incisores, a perpendicular compression only is necessary, without any lateral mo- tion, they are not so firmly fixed in their sockets as the other teeth are, each having only one short root, •f* ll 140 OF THE SKELETON. in the back part of the bone are covered by mei branes which allow small nerves to pass through the The two uppermost of these holes, especially on t fore side, are the largest; and as the bone descent the holes turn smaller. Sometimes a notch only * formed at the lower part in each side of this bone; a i in other subjects there is a hole common to it and t ‘ os coccygis, through which the twenty-ninth pair ' spinal nerves pass ; and frequently a bony bridge r formed on the back part of each side by a process se w up from the back part of the os coccygis, and join ' to the little knobs which the last bone of the os sacn " has instead of a spinal process. Under this bridge jugum, the twenty-ninth pair of spinal nerves runs ' its course to the common holes just now described. 1 The upper part of the body of the first bone resei bles the vertebrae of the loins; but the small fil 1 bone is oblong transversely and hollow in the midi 1 of its lower surface. Substance. The substance of the os sacrum is very spongy, wit ■ 1 out any considerable solid external plates, and is ligl er proportionally to its bulk than any other bone the body; but is secured from injuries by the thi muscles that cover it behind, and by the strong lie mentous membranes that closely adhere to it. As tl is one of the most remarkable instances of this sort defence afforded a soft weak bone, we may make t general observation. That wherever we meet wi such a bone, one or other, or both these defences a made use of; the first to ward off injuries, and the s cond to keep the substance of the bone from yieldi . too easily. onnexion. Thjs bone is articulated above to the last vertebra the loins, in the manner in which the lumbar verteh are joined; and therefore the same motions may performed here. The articulation of the lower par) the os sacrum to the os coccygis seems well adapted allowing considerable motion to this last bone, wen not much confined by ligaments. Laterally, the os crum is joined to the ossa ilium by an immoveable chondrosis, or what almost deserves the name of a si ture; for the cartilaginous crust on the surface of tl OF THE SKELETON. 141 ones is very thin, and both their surfaces are so sca- rous and unequal, as to be indented into each other ; . diich makes such a strong connexion, that great force required to separate them, after all the'muscles and gaments are cut. Frequently the two bones grow igether in old subjects. The uses of the os sacrum are, to serve as the com- Use?, i ion base and support of the trunk of the body, to i uard the nerves proceeding from the end of the spinal ; larrow, to defend the back part of the pelvis, and to ford sufficient origin to the muscles which move the unk and thigh. The bones that compose the os sacrum of infants, state at ive their bodies separated from each other by a thick Birth, irtilage; and, in the same manner as the true ver- brae, each of them consists of a body and two lateral ates, connected together by cartilages; the ends of le plates seldom being contiguous behind. ' : Os Coccygis*, or rump bone, is that triangular chain Os Coccy. 'bones depending from the os sacrum; each boners- I scorning smaller as they descend, till the last ends • most in a point. The os coccygis is convex behind, id concave before; from which crooked pyramidal ;ure, which was thought to resemble a cuckoo’s beak, ;, has got its name. This bone consists of four pieces in people of middle ;e:—Jn children, very near the whole of it is carti- ge: In old subjects all the bones are united, and be- me frequently one continued bone with the os sacrum. 1 The highest of the four bones is the largest, with i oulders extended farther to each side than the end of e os sacrum ; which enlargement should, in my opi- on, serve as a distinguishing mark to fix the limits either bone: and therefore should take away all dis- tte about reckoning the number of bones, of which enposed; or other which of these dispute two parts must of stillthe false be kept vertebra: up, sois ig as the numbering five or six bones in the os sa- 1 i Mm depends upon the uncertain accident of this broad i ouldered little bone being united to or separated * * O^aruyitv yogfw, caudas os, spondylium, os cucnli. 142 OF THE SKELETON. from it. The upper surface of this bone is a little ho ■- low. From the back of that bulbous part called it shoulders, a process often rises up on each side, to joi it with the bifurcated spine of the fourth and fifth bone ’ of the os sacrum, to form the bony bridge mentione n in the description of the os sacrum—Sometimes thes < shoulders are joined to the sides of the fifth bone of tb P os sacrum, to form the hole in each side common t f these two bones, for the passage to the twenty-nint. I® pair of spinal nerves. Immediately below the shoul W ders of the os coccygis, a notch may be marked on eacl « side, where the thirtieth pair of the spinal nerve » passes. The lower end of this bone is formed into i M small head, which very often is hollow in the middle, ii The three lower bones gradually become smaller >. and are spongy ; but are strengthened by a strong li gament which covers and connects them. Their ends to by which they are articulated, are formed in the sami it manner as those of the first bone. Between each of these four bones of young subject) n- a cartilage is interposed; therefore their articulatior i is analogous to that of the bodies of the vertebrae 011 the neck: For, as has been above remarked, thelowei <' end of the os sacrum and of each of the three superioi » bones of the os coccygis, has a small depression in the 1 middle; and the upper part of all the bones of the os coccygis is a little concave, and consequently, the in- lit terposed cartilages are thickest in the middle, to fill up both cavities; by which they connect the bones more firmly. When the cartilages ossify, the upper end o{ each bone is formed into a cavity, exactly adapted t® the protuberant lower end of the bone immediate!] above. From this sort of articulation, it is evident that, unless when these bones grow together, all them are capable of motion ; of which the first and s cond, especially this last, enjoys the largest share. The lower end of the fourth bone terminates ir rough point, to which a cartilage is appended. To the sides of these bones of the os coccygis, the|l .occygei muscles (a), and part of the levatoris ami ancM of the glutei maximi, are fixed. (a) Douglas, Myograph, chap. 40.—Eustach.-tab. 36. NoJ^l 45* 20. OF THE SKELETON. 143 The substance of these bones is very spongy; and * children cartilaginous, there being only a part of ■ e first bone ossified in a new-born infant. Since if erefore the intestinum rectum of children is not so jmly supported as it is in adults, this may be one rea- iji a why they are more subject to a procidentia ani i in old people (a). i From the description of this bone, we see how little i resembles the vertebrae; since it seldom has pro- ! ises, never has any cavity for the spinal marrow, nor i es for the passage of nerves. Its connexion hin- rs it from being moved to either side; and its mo- u backwards and forwards is much confined: Yet i its ligaments can be stretched by a considerable force, s a great advantage in the excretion of the fceces ., incc, and much more in child-bearing, that this bone ’ uld remain moveable ; and the right management it, in delivering women, may be of great benefit to m (6).—The mobility of the os coccygis diminish- \ ,i ; as people advance in age, especially when its liga- nts and cartilages have not been kept flexible by ig stretched, is probably one reason why women, i are old maids before they marry, have generally d labour in child-bed. 'he os coccygis serves to sustain the intestinum rec- ; and, in order to perform this office more effec- ly, it is made to turn with a curve forwards; by ch also the bone itself, as well as the muscles and iments, is preserved from any injury, when we sit i i our body inclined back. he second part of the trunk of the skeleton, the Pelvis. . .vrs, is the cylindrical cavity at the lower part of . abdomen, formed by the os sacrum, os coccygis, ossa innominata ; which last therefore fall now in Bse to be examined. Hhough the name of Ossa Innominata* contri-^" inno- i s nothing to the knowledge of their situation,minuta- ibture, or office; yet they have been so long and uni- ■ (atsm par.Spigel. 2. cap.de humani 3. corp. fabric, lib. 2. cap. 22.— Paaw, de ffl.. ISxsXiwv Paaw, ■rgarQutriis,ibid—Deventer, sacro conjuncta. Operat. cbirurg. cap. 27* 144 OF THE SKELETON. versally known by it, that there is no occasion 1 changing it. They are two large broad bones, whi ' form the fore part and sides of the pelvis, and the low - part of the sides of the abdomen. In children each 1 ' these bones is evidently divided into three ; which £ ■ afterwards so intimately united, that scarcely the lei 1 markoftheir former separation remains. Notwithstan r ing this, they are described as consisting each of thr f*,u< ■ bones, to wit, the os ilium, ischium, and pubis; whi I shall first describe separately, and then shall consid “ what is common to any two of them, or to all the thn • Os Ilium. Os Ilium*, or haunch-bone, is situated highest i“ the three, and reaches as far down as one-third of t * great cavity into which the head of the thigh-bone fa received. External The external side of this bone is unequally convc " Surface. and is called its dorsum ;—the internal concave si ?!' facesemicircular is by some edge (but at improperly) the highest named part itsof costa.this bor T fa which is tipped with cartilage in the recent subject, '4 named the spine, into which the external or descen ing oblique muscle of the abdomen is inserted; a: from it the internal ascending oblique and the trar •: verse muscles of the belly, with the gluteas maximi f quadratus lumborum, and latissimus dorsi, have thi origin. Some (a) are of opinion, that it is only t tendinous crust of all these muscles, and not a car lage, as commonly alleged, that covers this bony ed| The ends of the spine are more prominent than t surface of the bone below them; therefore are reckoj I: ed processes. From the anterior spinal process, 1 ' sartorius and fascialis^ muscles have their rise, and 1 outer end of the doubled tendon of the external oblic muscle of the abdomen, commonly called Fa Hoph or Poupart’s ligament, is fixed to it.—The inside the posterior spinal process, and of part of the spi forward from that, is made flat and rough where t sacrolumbalis and longissimus dorsi rise ; and to its oj (a)* Aayotm, Winslow, tcutut, Exposition scaphium, anatomique lumbare, clunium, du corps clavium, humain, a ti ies•f- os Tensor frais, §vaginae 96. femoris. Alb. E. Of THE SKELETON,. 145 ie are fixed ligaments, extended to the os sacrum and ansverse processes of the fifth and fourth vertebrae the loins [a). Below the anterior spinal process mds out another protuberance, which, by its situa- m,y the may epithet be distinguished of inferior, wherefrom thethe former,musculus by rectus add- iae* has its origin (5). Betwixt these two anterior acesses the bone is hollowed where the beginning the sartorius muscle is lodged. Below the posterior j nal process, a second protuberance of the edge of is bone is in like manner observable, which is closely plied to the os sacrum. Under this last process, a , isiderable large niche is observable in the os ilium; 1 ween the sides of which and the strong ligament t is stretched over from the os sacrum to the sharp j nted process of the os ischium of the recent subject, irge hole is formed, through which the musculus-py- ■ nmis, the great sciatic nerve, and the posterior cru- vessels pass, and are protected from compression, i rhe external broad side or dorsum of the os ilium is 1 ttle hollow towards the fore-part; farther back it ,s much raised; then is considerably concave ; and, , ly, it is convex. These inequalities are occasioned the action of the muscles that are situated on this Face. From behind the uppermost of the two an- or spinal processes, in such bones as are strongly ked by the muscles, a semicircular ridge is extend- ,o the hollow passage of the sciatic nerve. Between spine and this ridge, the gluteus medius takes its Immediately from above the lowest of the ante- spinal processes, a second ridge is stretched to the e. Between this and the former ridge, the glu- minimus has its origin. On the outside of the pos- •r spinal processes, the dorsum of the os ilium is md rough, where part of the musculus gluteus max- and pyriformis rise. The lowest part of this ft] is the thickest, and is formed into a large cavity aj high brims, to assist in composing the great ace- ffl Weitbrecht, Syndesmolog. sect. 4. § 39, 40, 46,4,7. iBlectusI! Baker, cruris Curs, Alb. osteolog. E. demonstr. 3. H 146 OP THE SKELETON. tabulum ; which shall be considered, after all the thn bones that constitute the os innominatum are describe Internal The internal surface of the os ilium is concave in i Surface. broadest fore part, where the internal iliac muscle h its origin, and some share of the intestinum ilium at colon is lodged. From this large hollow, a small 5 nuosity is continued obliquely forwards, at the insit of the anterior inferior spinal process, where part of ti psoas and iliacus muscles, with the crural vessels ai nerves, pass. The large concavity is bounded belc L by a sharp ridge, which runs from behind forward and, being continued with such another ridge of t , os pubis, forms a line of partition between the abd mon and pelvis. Into this ridge the broad tendon t the psoas parvus is inserted. All the internal surface of the os ilium, behind tl ' ridge, is very unequal: For the upper part is flat, b . spongy, where the sacrolumbalis and longissimus dc ; si rise. Lower down, there is a transverse ridge frc which ligaments go out to the os sacrum. Immediat ly below this ridge are placed the rough unequal c s, vities and prominences which are exactly adapted . those described on the side of the os sacrum. In t. same manner, the upper part of this rough surfacei {jorous, for the firmer adhesion of the ligamentous 0 t ular substance; while the lower part is more sol; and covered with a thin cartilaginous skin, for its ii moveable articulation with the os sacrum. From f ■; the circumference of this large unequal surface, lii ments are extended to the os sacrum, to secure md. firmly the conjunction of these bones. The passages of the medullary vessels are very cc 1 spicuous, both in the dorsum and costa of many a* 1 ilium; but in others they are inconsiderable. Substance. The posterior and lower parts of these bones thick ; but they are in general, exceedingly thin compact at their middle, where they are expose the actions of the musculi glutei and iliacus into and to the pressure of the bowels contained in belly. The substance of the ossa ilium is mostly lular, except a thin external table. Birth.State at In a ripe child, the spine of the os ilium is cai OF THE SKELETON. 147 nous, and is afterwards joined to the bone in form an cpiphyse.—The large lower end of this hone is >t completely ossified. Os Ischium* or hip bone, is of a middle bulk be- Os Ischium. 'een the two other parts of the os innominalum, is 1 uated lowest of the three, and is of a very irregular ure.—Its extent might be marked by an horizontal e drawn nearly through the middle of the acetabu- n; for the upper bulbous part of this bone forms 1 newhat less than the lower half of that great cavity, d the small leg of it rises to much the same height the other side of the great hole common to this ic and the os pubis. - from the upper thick part of the os ischium, a sharp Processes, cess, called by some spinous, stands out backwards, n which chiefly the musculis coccygeus and supe- ' ' gemellus, and part of the levator ani, rise; and the erior or internal sacrosciatic ligament is fixed to it. f ' between the upper part of this ligament and the i es it was formerly observed that the pyriform m\i$- - the posterior crural vessels, and the sciatic nerve, 3 out of the pelvis.—Immediately below this pro- ■ i, a sinuosity is formed for the tendon of the mus- ts obturator internus.—In a recent subject, this t of the bone, which serves as a pully on which the i .rator muscle plays, is covered with a ligamentous j i ilage, that, by two or three small ridges points out :: interstices of the fibres in the tendon of this mus- —The outer surface of the bone at the root of this : i ous process is made hollow by the pyriformis or us externus muscle. i elow the sinuosity for the obturator muscle is the j tknob or tuberosity, covered with cartilage or ten- (a). The upper part of the tuberosity gives rise ,«,!) ie inferior gemellus muscle. To a ridge at the in- of this, the external or posterior sacrosciatic liga- x i t is so fi xed, that between it, the internal ligament, the sinuosity of the os ischium, a passage is left for : jaternal obturator muscle. The upper thick smooth *(o) Coxae, Winslow, coxendicis, Exposit. pixis. anat. des os frais, § 96. 148 OF THE SKELETON. part of the tuber, called by some its dorsum, has t oblique impressions on it. The inner one gives oris \ to the long head of the biceps flexor tibice* and semim vosus f muscles, and the semimembranosus rises fn the exterior one, which reaches higher and nearer ( acetabulum than the other. The lower, thinner, mi scabrous part of the knob which bends forwards, is marked with two flat surfaces, whereof the internal what we lean upon when sitting, and the external gr rise to the largest head of the triceps adductor Jen ris X- Between the external margin of the tuberos: and the great hole of the os innominaium, there is fi quently an obtuse ridge extended down from the a. ? tabulum, which gives origin to the quadratus femor As the tuber advances forwards, it becomes small and is rough, for the origin of the musculus transvt salis || nnd erector penis. The small leg ef it, whi mounts upwards to join the os pubis, is rough and pi , minent at its edge, where the two lower heads of t Substance. tricepsThe orupper quadriceps and back adductor part or femoris the os §ischium take their is bro ri and thick ; but its lower and fore part is narrower a. thinner. Its substance is of the structure common broad bones. Connexion. The os ilium and pubis of the same side are the 01 bones which are contiguous to the os ischium. Birth.State at lum,The the part spinous of the process, os ischium the whichgreat formstuber, theand acetal the l curved leg, are all cartilaginous at birth. The tub with part of the leg or process above it, becomes^ epiphyse before this bone is fully formed. The Os Pubis IT, or share bone, is the least of t three parts of the os innominatutn, and is placed at Processes, upper fore-part of it. The thick largest part of bone is employed in forming the acetabulum ; fi * Biceps cruris Alb. E. + Semitendinosus Alb. JI J|| AdductorTransversus magnus perinaei femoris Alb. Alb.E. E. § AdductorHfins, pectinis, longus, penis, and A.pudibundum, brevis femoris fenestratum. Alb. E. OF THE SKELETON. 149 •hich becoming much smaller, it is stretched inwards* »its fellow of the other side, where again it grows rger, and sends a small branch downwards to join 1 ic end of the small leg of the os ischium. The upper re-part of each os pubis is tuberous and rough where e musculus rectus and pyramidalis are inserted, 1 rom this a ridge is extended along the upper edge of i te bone, in a continued line with such another of the ilium, which divides the abdomen and pelvis. The gament of Fallopius is fixed to the internal end of i■ is ridge, and the smooth hollow below it is made by e psoas and iliacus interims muscles passing with the iterior crural vessels and nerves behind the ligament. »me way below the former ridge, another is extended om the tuberous part of the os pubis downwards and ’;twards towards the acetabulum; between these two Iges the bone is hollow and smooth, for lodging the i tad of the pectineus muscle. Immediately below, f here the lower ridge is to take the turn downwards, a v i .nding niche is made, which is comprehended in the ) eat foramen of a skeleton, but is formed into a hole t a subtended ligament in the recent subject, for the ii ssage of the posterior crural nerve, and artery, and vein. The internal end of the os pubis is rough and tequal, for the firmer adhesion of the thick ligamen- us cartilage that connects it to its fellow of the other le: The process which goes down from that to the : ischium is broad and rough before, where the gra- ft ■ is and upper heads of the triceps, or rather quadri- ; y is adductor femoris have their origin. The substance of the os pubis is the same as of other Substance >: jad bones. Only a part of the large end of this bone is ossified, state at . - d the whole leg is cartilaginous, in a child born at Birth, e full time. Betwixt the os ischium and pubis is left a very large Thyroid ij egularshield, hole,has beenwhich, called from thyroides. its resemblance This holeto a is door all, hole, cept the niche for the posterior crural nerve, filled 3 in a recent subject with a strong ligamentous mem- : e) me, that adheres very firmly to its circumference. * Mesiad. E. 150 OF THE SKELETON. From this membrane chiefly the two obturator musch ‘ external and internal, take their rise. The great cl sign of this hole, besides rendering the bone lighter, > to allow a strong enough origin to the obturator mu k cles, and sufficient space for lodging their bellies, ti I there may be no danger of disturbing the functions te the contained viscera of the pelvis by the actions of t fe internal, nor of the external being bruised by t thigh bone, especially by its lesser trochanter, in t ^ motions of the thigh inwards; both which inconver encies must have happened, had the ossa innomina been complete here, and of sufficient thickness ai * strength to serve as the fixed point of these musch *S The bowels sometimes make their way through t fe niche for the vessels, at the upper part of this thyra ft1 hole, and this causes a hernia in this place (a). In the external * surface of the ossa innominat near the outside of the great hole, a large deep cavi »ji is formed by all the three bones conjunctly : For tl :"i os pubis constitutes about one fifth; the os ilium mak ll something less than two fifths, and the os ischium much more than two fifths. The brims of this cavil are very high, and are still much more enlarged by tl ligamentous cartilage, with which they are tipped i W a recent subject.. From this form of the cavity it h: been called acetabulum; and for a distinguishir tki character, the name of the bone that constitutes tl largest share of it is added; therefore acetabulum oss isehii t is the name this cavity commonly bears.- v Hound the base of the supercilia, the bone is rough an f unequal, where the capsular ligament of the articuli itii; tion is fixed. The brims at the upper and back pal i of the acetabulum are much larger and higher than ani where else ; which is very necessary to prevent tb head of the femur from slipping out of its cavity j ■'t this place, where the whole weight of the body beal i: upon it, and consequently would otherwise be cobh stantly in danger of thrusting it out. As these brinllp *(a) Lateral. Memoires E. de Pacad. de chirurgie, tom.t Coxae, 1. p. coxendicis.709, &c. ji ► ' OF THE SKELETON. 151 'ire extended downwards and forwards, they become S ess; and at their internal lower part a breach is made n them; from the one side of which to the other, a igament is placed in the recent subject: under which s left a large hole, which contains a fatty cellular sub- j itance and vessels. The reason of this appearance has I ifforded matter of debate. To me it seems evidently i jontrived for allowing a larger motion to the thigh in- vards : For if the bony brims had been here continu- id, the neck of the thigh bone must have struck upon ;hem when the thighs were brought across each other ; , vhich, in a large strong motion this way, would have endangered the neck of the one bone, or brim of the •ther. Then the vessels which are distributed to the oint may safely enter at the sinuosity in the bottom if the breach; which being however larger than is , tecessary for that purpose, allows the large mucila- . pnous gland of the joint to escape below the liga- j aent, when the head of the thigh bone is in hazard of iressing too much upon it in the motions of the thigh utwards (a). Besides this difference in the height of he brims, the acetabulum is otherwise unequal: For he lower internal part of it is depressed below the . artilaginous surface of the upper part, and is not co- rered with cartilage ; into the upper part of this parti- ular depression, where it is deepest and of a similunar ' orm, the ligament of the thigh-bone, commonly, hough improperly, called the round one, is inserted ; idiile in its more superficial lower part the large muci- iginous gland of this joint is lodged. The largest share f this separate depression is formed in the os ischium. From what has been said of the condition of the 1 hree bones composing this acetabulum in new-born hildren, it must be evident that a considerable part f this cavity is cartilaginous in them. The ossa innominata are joined at their back part Connexion 5 each side of the os sacrum by a sort of suture, with of the ossa .' i very thin intervening cartilage, which serves as so innominata. i inch glue to cement these bones together; and strong * igaments go from the circumference of this unequal (a) Petit, Memoires de 1’acad. des sciences, 1722. 152 OF THE SKELETON. surface, to connect them more firmly. The ossa inn : minata are connected together at their fore-part by tl ligamentous cartilage interposed between the two osi ; pubis. These bones can therefore have no motion i :1 1 a natural state, except what is common to the trunk • the body, or to the os sacrum. But it has been dh ' puted, whether or not they loosen so much from eac ' other and from the os sacrum, in child-birth, by tl , flow of mucus to the pelvh, and by the throws of tl j*? labour, as that the ossa pubis recede from each othe: , and thereby allow the passage between the bones t 1 be enlarged. Several observations (a) shew that th: , relaxation sometimes happens.. But those who had fre ' quently opportunities of dissecting the bodies of wome who died immediately after being delivered of childrei: I' teach us to beware of regarding this as the commo: ‘ ‘ effect of child-birth ; for they found such a relaxatio: ' in very few of the bodies which they examined (6) ’ Considering what great weight is supported in ou ‘ erect posture, by the articulation of the ossa innomi ■- nata with the os sacrum, there is great reason to thin! '; that if the conglutinated surfaces of these bones wen l,: • once separated, (without which, the ossa pubis canno; r r shuffle on each other,) the ligaments would be vio lently stretched, if not torn; whence many disorder! would arise (c). Each os innominatum affords a socket (the acelabtl- lum) for the thigh bones to move in, and the trunk oj| ' the body rolls here so much on the heads of the thighjj ' bones, as to allow the most conspicuous motions of th( 1 trunk, which are commonly thought to be performed bl l! i the bones of the spine. This articulation is to be mon : fully described after the ossafemoris are examined. The pelvis then has a large opening above where ifll! is continued with the abdomen, is strongly fenced bj" bones on the sides, back, and fore-part, and appear 2. (аcap.) Bauhin. 24.—Riolan. Theat. Anthropogr.anat. lib. 1. cap.lib. 49.—Spigel.6. cap. 12.— Anat. libl broeck.(б) Hildan. Anat. lib.Epist. 9. cap.cent. 16.obs. 46—Dionis, Sixieme demons des(p) os.—Morgagn. Ludov. in Ephem. Advers. Germ. 3. animad. dec. 1. 15.ann. 3, obs. 255. OF THE SKELETON. 153 ith a wide opening below, in the skeleton; but, in ic recent subject, a considerable part of the opening I filled by the sacrosciatic ligaments, pyriform, inter- il obturator, levatores ani,gemim and coccygei muscles, hich support and protect the contained parts better i an bones could have done ; so that space is left only the lowest part of it, for the large exeretories the sica urinaria, intestimm rectum, and in females, the eras, to discharge themselves. The Thohax *, or chest, which is the only part o( Thorax. e trunk of the body which we have not yet describ- 1, reaches from below the neck to the belly ; and, by cans of the bones that guard it, is formed into a •ge cavity, the figure of which is somewhat conoidal; ; ent its for upper the passage smaller of theend wind-pipe, is not finished, gullet, being and large left iiod-vessels; and its lower part, or base, has no bones, d is shorter before than behind; so that, to carry on : r comparison, it appears like an oblique section of I e conoid. Besides which, we ought also to remark, neft theway lower above part(a) ; ofarid this that cavity the middleis narrower of its backthan rt is considerably diminished by the bones standing i wards into it. The bones which 'form the thorax are the twelve rsal vertebrce behind, the ribs on the sides, and the rnum before. The vertebrce have already been described as part the spine; and therefore are now to be passed. The Ribs, or costae t, (as if they were custodes, or Ribs, irds, to those principal organs of the animal ma- 1. ne, the heart and lungs,) are the long crooked bones ced at the sides of the chest, in an oblique direction vqwards in respect of the back-bone. Their num- is generally twelve on each side; though frequently ven or thirteen have been found (5).—Sometimes ,'r. Pectus,UXtvgat, cassum. a-sgis-igra, rtrectai, (a) Albin. de ossib. § 169. )per, Riolan. Explicat. Comment, tab. 93 de and ossibus. 94—Morgagu. cap. 19—Marchetti. Advers. anft. cap. 5}, H 5 154 OF THE SKELETON. the ribs are found preternaturally conjoined or divii ed-(a). The ribs are all concave internally; where they a also made smooth by the action of the contains h parts, which, on this account, are in no danger of b ing hurt by them ; and they are convex externall that they might resist that part of the pressure of tl atmosphere, which is not balanced by the air with the lungs, during inspiration. The ends of the ri next the vertebrae are rounder than they are after the bones have advanced forwards, when they becon flatter and broader, and have an upper and lower edg each of which is made rough by the action of the i: tercostal muscles inserted into them. These muscle being all of nearly equal force, and equally stretched the interstices of the ribs, prevent the broken ends these bones in a fracture from being removed far 01 of their natural place, to interrupt the motion of tl vital organs. The upper edge of the ribs is more tuse and rounder than the lower, which is depresse 1te on its internal side by a \ong fossa, for lodging the ii tercostal vessels and nerves; on each side of whic there is a ridge, to which the intercostal muscles ai fixed. The fossa is not observable however at eithi end of the ribs ; for at the posterior or root, the vei sels have not yet reached the ribs ; and, at the fore-en they are split away into branches, to serve the pari 1' f between the ribs; which plainly teaches surgeons 01 reason of the greater safety of performing the open tion for the empyema towards the sides of the thora than either near the back or the breast. At the posterior end *' of each rib, a little head i formed, which is divided by a middle ridge into tw plain or hollow surfaces ; the lowest of which is tk broadest and deepest in most of them. The two plain are joined to the bodies of two different vertebrae, anl the ridge forces itself into the intervening cartilag A little way from this head, we find, on the extern surface, a small cavity, where mucilaginous glanfl *(a) Kxtuv, Sue, Trad,remulus. d’osteolog. Dorsal p. end. 141. E. THE SKELETON. Hire lodged; and round the head, the bone appears pongy, where the capsular ligament of the articula- ■ ion is fixed. Immediately beyond this, a flatted tu- icrcle rises, with a small cavity at, and roughness ' bout its root, for the articulation of the rib with the ,, l ransverse process of the lowest of the two vertebrae, /ith the bodies of which the head of the rib is joined, i Advancing further on this external surface, we ob- erve in most of the ribs another smaller tubercle, into . ; rhich ligaments which connect the ribs to each other, nd to the transverse processes of the vertebrae andpor- .ions of the longissimus dorsi, are inserted. Beyond his the ribs are made flat by the sacro-lumbalis ..iiuscle, which is inserted into the part of this flat urface farthest from the spine, where each rib makes 'i, considerable curve, called by some its angle. Then j he rib begins to turn broad, and continues so to its | nterior end*, which is hollow and spongy, for the re- eption of, and firm coalition with the cartilage that Lins thence to be inserted into the sternum, or to be lined with some other cartilage. In adults, generally he cavity at this end of the ribs is smooth and polish- d on its surface; by which the articulation of the irtilage with it has the appearance of being designed ir motion ; but it has none. The substance of the ribs is spongy, cellular, and Substance, overed only with a very thin external lamellated sur- ice, which increases in thickness and strength as it pproaches the vertebrae. ! To the fore end of each rib a long broad and strong Articulat-n Cartl irtillage is fixed, and reaches thence to the sternum, jagesS - r is joined to the cartilage of the next rib. This ‘ ourse, however, is not in a straight line with the rib; ‘ jr generally the cartilages make a considerable curve, «ie concave part of which is upwards; therefore, at i ijjheir insertion into the sternum, they make an obtuse angle above, and an acute one below. These carti- Miges are of such a length as never to allow the ribs to abome to a right angle with the spine; but they keep t! hem situated so obliquely, as to make an angle very * nxar»i, palmula. SternalH 6end. E. 156 OF THE SKELETON. considerably obtuse above, till a force exceeding th t elasticity of the cartilages is applied. These cartilages r_-- as all others, are firmer and harder internally, tha; they are on their external surface ; and sometimes, i; t. old people, all their middle surface becomes bony s» while a thin cartilaginous lamella appears external trw ly (a). The ossification, however, begins frequently a ffie the external surface. The greatest alternate motion »ck of the cartilages being made at their great curvature ke that part remains frequently cartilaginous, after al I the rest is ossified (6). tion.Articula- theThe one ribs behind then isare doubly articulated joined atto eachthe end,vertebra; of whicl foi ans the head is received into the cavities of two bodies, o: the vertebrae, and the larger tubercle is received intc the depression in the transverse process of the lowei t uerteira.—When one examines the double articulation nl* he must immediately see, that no other motion can 3 here be allowed than upwards and downwards; since st the transverse process hinders the rib from being ^ thrust back; the resistance on the other side of the i sternum prevents the ribs coming forward ; and each m of the two joints, with the other parts attached, op* (•- poses its turning round. But then it is likewise as £ evident, that even the motion upwards and downward^ ?! caq be but small in any one rib at the articulation it-j If* self. But as the ribs advance forwards, the distance at from their centre of motion increasing, the motion )? must be larger; and it would be very conspicuous at, i. their anterior ejids, were they not resisted there by the«?. cartilages, which yield so little, that the principal mo- tion is performed by the middle part of the ribs, which turns outwards and upwards, and occasions the twist remarkable in the long ribs at the place near their fore- end where they are most resisted (c). Varieties. nexionHitherto which I havemost laidof the down ribs theenjoy, structure as belonging and con- to all of them; but must npw consider the specialties (a) Vesal. lib. 2. cap. 19. (c)(4) Winslow,Havers. Osteolog. Memoires novdisc. de 1’acad. 5. desp. sciences,289. 1720. OF THE SKELETON. 157 i vherein any of them differ from the general descrip- ;ion given, or from each other. , In viewing the ribs from above downwards, their , igure is still straighter ; the uppermost being the most r rooked of any. Their obliquity in respect of the spine icreases as they descend; so that though their dist- ance from each other is very little different at their iack part, yet at their fore ends the distances between he lower ones must increase. In consequence, too, £ this increased obliquity of the lower ribs, each of heir cartilages makes a greater curve in its progress irom the rib towards the sternum ; and the tubercles, hat are articulated to the transverse processes of the irtebrne, have their smooth surfaces gradually facing « lore upwards. The ribs becoming thus more oblique, u 'hile the sternum advances forwards in its descent, [lakes the distance between the sternum and the ante-. ■ or end of the lower ribs greater than between the , ernum and the ribs above; consequently'the carti- > ges of those ribs that are joined to the breast bone :e longer in the lower than in the higher ones. These ; ■ irtilages are placed nearer to each other as the ribs escend, which occasions the curvature of the carti- ges to be greater. . The length of the ribs increases from the first and opermost rib, as far down as the seventh; and from lat to the 12th, as gradually diminishes. The supe- or of the two plain, or rather hollow surfaces, by hich the ribs are articulated to the bodies of the ver- ... brae, gradually increases from the first to the fourth . 3, and is diminished after that in each lower rib.— lie distance of their angles from the heads always in- eases as they descend to the ninth, because of the I eater breadth of the sacrolumbalis muscles (a). I The ribs are commonly divided into true andfalse. The true* costae are the seven upper ones of each Tme Ribs. ie, whose cartilages are all gradually longer as the is descend, and are joined to the breast bone; so at being pressed constantly between two bones, they a ilj l" )Tvntrxi, Winslow, Germanae, Exposition legitimae. anatomique des os secs, § 613. 158 OF THE SKELETON. are flatted at both ends, and are thicker, harder, anc i more liable to ossify, than the other cartilages that an a not subject to so much pressure. These ribs include the heart and lungs ; and therefore are the proper ol i False Ribs. trueThe custodes five inferior of life. ribs of each side are the false o : Bastard*, whose cartilages do not reach to the ster ^ num; and therefore, wanting the resistance at thei ip fore part, they are there pointed ; and, on this account ta having less pressure, their substance is softer.—Tin it; cartilages of these /a/^e ribs are shorter as the ribs de n scend. To all these five ribs the circular edge of tin i diaphragm is connected ; and its fibres, instead of be r perpendicularing stretched immediately to the ribs, aretransversely, pressed so andas to so be running often t(» especially in expiration, parallel to the plane in whicl tf the ribs lie: Nay, one may judge by the attachments i- which these fibres have so frequently to the sides o! the thorax, a considerable way above where their ex j,: tremities are inserted into the ribs, and by the situa- i1 tion of the viscera, always to be observed in a deac subject laid supine, that there is constantly a largs & concavity formed on each side by the diaphragm with- i»} in these bastard ribs, in which the stomach, liver,' > spleen, &c. are contained; which, being reckoned i only among the viscera naturalia, have occasioned the ? name of bastard custodes to these bones. Hence in simple fractures of the false ribs, withou f fever, the stomach ought to be kept moderately fille< (. with food, lest the pendulous ribs falling inwardi [; should thereby increase the pain, cough, &c. (a).-3 ; Hence likewise we may learn how to judge better oil the seat of several diseases, and to do the operation foff the empyema, and some others, with more safety thafl we can do, if we follow the common directions. J The eight upper ribs were formerly (b) classed inti pairs, with particular names to each two, to wit, the* crooked, the solid, the pectoral, the twisted: But thes® *Mak0*Hcu, xavtai, &rivii, poxi, adulterine, spuril illegitime.(a) Hippocrat. de articulo, § 51. Pare, lib. 15. cap. 11. part.(5) 3.Laurent. cap. 2. Hist. anat. lib. 2. cap. 29. Paaw, de ossibus OF THE SKELETON. 159 are of so little use, that they are now generally ij neglected. The first rib of each side is so situated, that the flat First Ri!>. iides are above and below, while one edge is placed 1 nwards, and the other outwards, or nearly so ; there- i ore sufficient space is left above it for the subclavian :i "essels and muscle; and the broad concave surface is ■ , pposed to the lungs: But then, in consequence of his situation, the channel for the intercostal vessels is iot to be found, and the edges are differently formed ; rom all the others except the second ; the lower one >eing rounded, and the other sharp. The head of this ib is not divided into two plain surfaces by a middle idge, because it is articulated only with the first ver- , ibra of the thorax. Its cartilage is ossified in adults, ’ nd is united to the sternum at right angles. Fre- aently this first rib has a ridge rising near the mid- le of its posterior edge, where one of the heads of . re scalenus muscle rises. Farther forward it is flatted, r sometimes depressed by the clavicle, i The fifth, sixth, and seventh, or rather the sixth, 5th—10th. i sventh, eight, and sometimes the fifth, sixth, seventh, ighth, ninth ribs, have their cartilages at least con- iguous ; and frequently they are joined to each other y cross cartilages; and most commonly the cartila- • es of the eighth, ninth, tenth, are connected to the >rmer and to each other by firm ligaments. ... The eleventh, and sometimes the tenth rib, has no nth. , i ibercle for its articulation with the transverse process , : the vertebra, to which it is only loosely fixed by gaments.sin the upper The ribs, fossa because in its lowerthe vessels edge isrun not more so deep to- . ards the interstice between the ribs.—Its fore end is . 11 nailer than its body, and its short small cartilage is at loosely connected to the cartilage of the rib above. The twelfth rib is the shortest and straightest.—Its 18th. i ead is articulated only with the last vertebra of the iorax; therefore is not divided into two surfaces— a his rib is not joined to the transverse process of the s 'rtebra, and therefore has no tubercle, being often 31 ailed necessarily inwards by the diaphragm, which H i articulation with the transverse process would not 3 ive allowed.—The fossa is not found at its under OF THE SKELETON. edge, because the vessels run below it. The fort part of this rib is smaller than its middle, and has only a very small-pointed cartilage fixed to it. Tc ; its whole internal side the diaphragm is connected. The motions and uses of the ribs shall be more parti Stale at cularly'The treatedheads and of, aftertubercles the descriptionof the ribs ofof thea new-borr sternum 't • child have cartilages on them ; part of which becomt hi, afterwards thin epiphyses. The bodies of the ribi » encroach gradually after birth upon the cartilages hr so that the latter are proportionally shorter, when com- u pared to the ribs in adults, than in children. Here I cannot help remarking the wise providenct ■ of our Creator, in preserving us from perishing as i soon as we come into the world. The ends of the t bones of the limbs remain in a cartilaginous state toy after birth, and are many years before they are en- lit tirely united to the main body of their several bones , i whereas the condyles of the occipital bone, and of the lower jaw, are true original processes, and ossified be- fore birth, and the heads and tubercles of the ribs are & nearly in the same condition; and therefore the weight is of the large head is firmly supported ; the actions of • sucking, swallowing, respiration, &c. which are indis-i fe pensably necessary for us as soon as we come into th< > > world, are performed without danger of separating tin r,. parts of the bones that are most pressed on in thes< tv motions: Whereas, had these processes of the head, ‘i jaw, and ribs, been epiphyses at birth, children must !• have been exposed to danger of dying by such a sepa i ration; the immediate consequences of which woulj t - be the compression of the beginning of the spinal mar t row, or want of food, or a stop put to respiration. Sternum. bone,The or Sternum*, pile of bones, or atbreast-bone, the fore part is theof thebroad thoras fla —The number of bones which this should be divide< i into, has occasioned debates among anatomists, wh< t have considered it in subjects of different ages. In adults of a middle age, it is composed of three bonef which easily separate after the cartilages connectinj them are destroyed. Frequently the two lower bone * 'ZrrUcs, os pectoris, ensiforme, scutum cordis. THE SKELETON.. 161 e found intimately united; and very often in old ople, the sternum is a continued bony substance from e end to the other; though we still observe two, }netimes marks ofthree the transverseformer divisions. lines on its surface; which When we consider the sternum as one hone, we find broadest and thickest above, and becoming smaller it descends. The internal * surface of this bone is i newhat hollowed for enlarging the thorax ; but the ivexity on the external t surface is not so conspicu- ; >, because the sides are pressed outwards by the true i s ; the round heads of whose cartilages are received seven smooth pits, formed in each side of the ster- ;, w,□ and are kept firm there by strong ligaments, i ich on the external surface have a particular radiat- texture (a)—Frequently the cartilaginous fibres ust themselves into the bony substance of the sler- n, and are joined by a sort of suture. The pits at j ceupper one frompart, ofanother, the sternum and as arethey at descend, the greatest are near- dis- so that the two lowest are contiguous. The substance of the breast-bone is cellular, with ery thin external plate, especially on its internal face, where we may frequently observe a cartilagi- s crust spread over it (6). On both surfaces, how- r, a strong ligamentous membrane is closely braced; the cells of this bone are so small, that a consider- : quantity of osseous fibres must be employed in the position of it: Whence, with the defence which muscles give it, and the moveable support it has i the cartilages, it is sufficiently secured from being ten ; for it is strong by its quantity of bone ; its ;s are kept together by ligaments; and it yields rgh to elude considerably the violence offered (c). 0 far may be said of this bone in general; but the Division, e bones, of which, according to the common ac- tt,'it is composed in adults, are each to be examined. \w jirst, + all agree, is somewhat of the figure of a Upper Part. DCentral. Ruysch. E.Catalog, rar. fig. 9 Peripheral. E. 1 Jac. Sylv. in Galen, de ossibus, cap. 1. Xfufti,, Senac. jugulum,in Memoires farcula de 1’acad. superior. des sciences, 1724, OF THE SKELETON. heart, as it is commonly painted; only it does not 11 minate in a sharp point. This is the uppermost thi )• est part of the sternum. The upper middle part of this first bone, where i f thickest, is hollowed to make place for the trachea teria; though this cavity is formed principally by bone being raised on each side of it, partly by the c , vicles thrusting it inwards, and partly by the ster id * mastoidei muscles pulling it upwards. On the outs w- of each tubercle, there is an oblong cavity, that, laic viewing it transversely from before backwards, appe; fo a little convex : Into these glence the ends of the c U vicles are received. Immediately below these, the sii li of this bone begin to turn thinner ; and in each a s« perficial cavity or a rough surface is to be seen, wht it the first ribs are received or joined to the sternum.— =•■ the side of the under end of this first bone, the hahK the pit for the second rib on each side is formed. T i upper part of the surface behind is covered with | strong ligament, which secures the clavicles ; and afterwards to be more particularly taken notice of. f Middle The second or middle division of this bone, is mu p Part. longer, narrower, and thinner than the first; but, 4 L cepting that it is a little narrower above than behj |l it is nearly equal all over in its dimensions of breadl L: or thickness. In the sides of it are complete pits L' the third, fourth, fifth, and sixth ribs, and half of 1 pits for the second and seventh; the lines, which i marks of the former division of this bone, being tended from the middle of the pits of one side to ■1 middle of the corresponding pits of the other sidej Near its middle an unossified part of the bone is sob times found, which, freed of the ligamentous membri or cartilage that fills it, is described as a hole: ana this place, for the most part, we may observe a tra| verse line, which has made authors divide this bJ into two—When the cartilage between this and I first bone is not ossified, a manifest motion of this ufl the first may be observed in respiration or in raiq the sternum, by pulling the ribs upwards or distendl the lungs with air in a recent subject. Cartilage.Ensiform The third bone is much less than the other two, aibc| OF THE SKELETON. 163 «as only one-half of the pit for the seventh rib formed ; l it; wherefore it might be reckoned only an appen* x of the sternum. In young subjects it is always i l irtilaginous, and is better known by the name of nrtilago xipkoides or ensiformis* than any other ; i ough the ancients often called the whole sternum en- : f'orme, comparing the two first bones to the handle, id this appendix to the blade of a sword.—This third une is seldom of the same figure, magnitude, or si- ,. ation in any two subjects; for sometimes it is a plain i iangular bone, with one of the angles below, and ij rpendicular to the middle of the upper side, by i rich it is connected to the second bone.—In other i ople the point is turned to one side, or obliquely s': ‘wards or backwards. Frequently it is all nearly of i- equal breadth, and in several subjects it is bifur- :i ;ed: whence some writers give it the name of fur- la or furcula inferior; or else it is unossified in the : ddle In the greatest number of adults it is ossified : d tipped with a cartilage; in some, one half of it is .: ‘tilaginous, and in others it is all in a cartilaginous , ite.—Generally several oblique ligaments fixed at ] e end to the cartilages of the ribs, and by the other > the outer surface of the xiphoid bone, connect it i • only to those cartilages (a). So many different ways this small bone may be med, without any inconvenience: But then some these positions may be so directed, as to bring on a rat train of ill consequences; particularly when the er end is ossified, and is too much turned outwards nwards (6), or when the conjunction of this appendix . h the second bone is too weak (c). f - Clypealis, gladialis, mucronata, malum, granatum, scutum 4 s lachi,ensiculata. epiglotalis cultralis, medium furculae inferioris, scutifor- J ' >)i) Rolfinc.Weitbrecht, Dissert. Syndesmolog. Anat. lib. p. 2. 121. cap. 41.—Paaw, de ossib. •4 ;in..1. mucronat.cap. 3. and part. 3. cap. 3.—Codronciu de prolapsu car- ■ i.rl:1 ■ilchret.) Paaw, anat.ibid tom.Borrich. 2. lib. act. 3. Hafn.§ 5. vol.Append, 5. ob. ad. 79-—Bonet, obs. 8. et 9 § 7- obs. 19. 164 OF THE SKELETON. Connexion. perThe ribs, sternum unless iswhen joined the by first cartilages coalesces to withthe sevei it i t( intimate union of substance; and its unequal c | ■ on each side of its upper end is fitted for the en it- the clavicles. Birth.State at bones,The sternumsurrounded most with frequently cartilage, has in fourchildren round bo s t,. the full time; the uppermost of these, which is the U bone, being the largest. Two or three other very s i- > bony points are likewise to be seen in several chib The number of bones increases for some years, tr then diminishes, but uncertainly, till they are at » united into those above described of an adult. r Uses. sertionThe usesto several of this muscles; bone are, to tosustain afford the origin mediasth and t. to defend the vital organs, the heart and lungs, af fore-part ; and, lastly, by serving as a moveable n crum of the ribs, to assist considerably in respirat i Which action, so far as it depends on the motion of i bones, we are now at liberty to explain. theMotions Ribs of gesWhen to the the sternum, ribs that or to are the connected cartilages byof thetheir true car i ili. andtium. Ster- areu beacted p H uponl from by thethe obliqueintercostal position muscles, which they their n e)* tilagesa keptU e( them in, nearer to right angles with vertebrae and sternum, because the first or uppern if. rib is by much the most fixed of any; and the cartils ' making a great resistance to raising the anterior e ■ of the ribs, their large arched middle parts turn o *t wards as well as upwards. The sternum, pressed strc ly on both sides by the cartilages of the ribs, is pt , ed forwards, and that at its several parts, in prop ■ tion to the length and motions of its supporters, ribs ; that is, most at its lower end. The sternum i the cartilages, thus raised forwards, must draw the c phragm connected to them; consequently so far stre it, and bring it nearer to a plane. The power that rs ed this bone and the cartilages, fixes them sufficien to make them resist the action of the diaphragm, wh fibres contract at the same time, and thrust the visa of the abdomen downwards. The arched part of i ribs being thus moved outwards, their anterior el OP THE SKELETON. 165 ! id the sternum being advanced forwards, and the dia- liragm being brought nearer to a plain surface, in- ead of being greatly convex on each side within each ivity of the thorax, it is evident how considerably the ivity, of which the nine or ten upper ribs are the sides, I ust be widened, and made deeper and longer. While ! iis is doing in the upper ribs, the lower, whose carti- Hi ges are not joined to the sternum, or to other cartila- ts, move very differently, though they conspire to the / ime intention, the enlargement of the thorax : For si iving no fixed point to which their anterior ends are ! stened, and the diaphragm being inserted into them s the place where it runs pretty straight upwards from j S origin at the 'vertebrae, these ribs are drawn down- ards by this strong muscle, and by the muscles of i je abdomen, which, at this time, are resisting the retching force of the bowels ; while the intercostal ! iuscles are pulling them in the contrary direction, to i it, upwards : The effect therefore of either of these iwers, which are antagonists to each other, is very ; tie, as to moving the ribs either up or down ; but the ■ uscles of the abdomen, pushed at this time outwards u the viscera, carry these ribs along with them. Thus lie thorax is not only not allowed to be shortened, but |j really widened at its lower part, to assist in making <4 1fficient space for the due distension of the lungs. As soon as the action of these several muscles ceases, e elastic cartilages extending themselves to their i tural situation, depress the upper ribs, and the ster- m subsides;—the diaphragm is thrust up by the vis- -a abdominalia, and the oblique and transverse mus- is of the belly serve to draw the inferior ribs inwards the satne time. By these causes the cavity of the ’ast is diminished in all its dimensions. Though the motions above described of the ribs and • mum, especially of the latter bone, are so small in ii e mild respiration of a healthy person, that we can i ircely observe them; yet they are manifest when- sr we designedly increase our respiration, or are ob- ed do it after exercise, and in several diseases*. ' On this subject, see Barcl. Muscul. Mot. p. 514. E. 166 OF THE SKELETON. OP THE SUPERIOR EXTREMITIES. Division. Authors are much divided in their opinions abo i the number of bones which each superior extremity i t should be said to consist of, some describing the cL : vide and scapula as part of it, others classing the b* two bones with those of the thorax : But since mo it» quadrupeds have no clavicles, and the human thort lire can perform its functions right when the scapula tt* taken away (a), whereas it is impossible for us to ha’ U the right use of our arms without these bones; I mu : ip think that they belong to the superior extremities :r and therefore shall divide each of them into the skou . Shoulder. der,The arm, Shoulder fore-arm, consistsand hand. of the clavicle and scapuL 4’ Clavicle. in Clavicula,figure like an or collar-bone^Italic f, placed is the almost long crookedhorizontal! bon aSii between the upper lateral part of the sternum and whs ft is commonly called the top of the shoulder, which, as < clavis or beam, it bears olf from the trunk of the bod; i The clavicle, as well as other long round bones, s; larger at its two ends, than in the middle. The en Si next to the sternum + is triangular: The angle behin W is considerably produced, to form a sharp ridge, t |ty which the transverse ligament extended from one els vide to the other is fixed (6). The side opposite II tt? this is somewhat rounded. The middle of this pre tuberant end is as irregularly hollowed, as the cavit in the sternum for receiving it is raised; but in a re cent subject, the irregular concavities of both are sup i plied by a moveable cartilage, which is not only muci j more closely connected everywhere by ligaments t * KuXa, yua, ixfualit;. Enata, adnata, explanata membi i. artus.(а) Philosoph.Atlantal extremity,transact, numb. Bard. 449. E. § 5. busdam.-j- Os jugulare, jugulum, furcula, ligula, clavis, humerus qtt* J(б )naganfctyis. Kiolan, Encheirid. Anat. lib. 6. cap. 13. Winslow, Et tom.pos. Anat.iv. p. 255.des etos Syndesmolog,frais, § 248. sect.Weitbrecht, 2. 1. § 3. Act. Petropoli [E SKELETON. 167 circumference of the articulation, than those of the /er jaw ; but it grows to the two bones at both its ernal * and external f end ; its substance at the in- nal end being soft, but very strong, and resembling intervertebral cartilages (a). i'rom this internal end, the clavicle, for about two i hs of its length, is bended obliquely forwards and vnwards. On the upper and fore part of this cur- i ure a small ridge is seen, with a plain rough sur- u e before it; whence the musculis sterna hyoideus l sterno-masloideus have in part their origin. Near : lower angle a small plain surface is often to be ■ , larked, where the first rib and this bone are con- i nous (b), and are connected by a firm ligament (c). im this a rough plain surface is extended out- rds, where the pectoral muscle has part of its origin. ; iiind, the bone is made flat and rough by the in- . | cion of the larger share of the subclavian muscle. : ;er the clavicle begins to be bended backwards, it i round, but soon after becomes broad and thin ; i :ch shape it retains to its external end. Along the ernal X concavity runs a rough sinuosity, from ; ch some part of the deltoid muscle takes its rise - j )pposite to this, on the convex edge, a scabrous 'e gives insertion to a share of the cucullaris mus- The upper surface of the clavicle here is flat; . the lower is hollow, for lodging the beginning of musculis subclavius; and towards its back part s a tubercle, to which, and a roughness near it, the ng short thick ligament connecting this bone to coracoid process of the scapula is fixed. ’he external end § of this bone is horizontally Ob- 5, smooth, sloping at the posterior side, and tipped recent subject with a cartilage, for its articulation a the acromion scapulae. Round this the bone is ihgy, for the firmer connection of the ligaments, fl'he medullary arteries having their direction ob- Foramina. * Proximal. E. f Distal. E. (A)(a) Dionis,Weitbrecht, Sixieme Syndesmolog. demonst. des sect. os. 2. 1. § 6. (c)? Sterno-lateral. Weitbrecht, Syndesmolog.E. sect. 2.§ ’Ea-w/ws.I. § 7- 168 OP THE SKELETON. liquely outwards, enter the clavicles by one or me ,i small passages in the middle of their back part. Substance. The substance of this bone is the same as that i Connexion. theThe other triangular round long unequal bones. interior end of each clav t cle has the cartilage above described interposed b twixt it and the irregular cavity of the sternum. T1 it ligaments, which surround this articulation to secu: to it, are so short and strong, that little motion can 1 tt allowed any way; and the strong ligament that is stretched across the upper furcula of the sternum, fro iw the posterior prominent angle of the one clavicle, i,. the same place of the other clavicle, serves to kec fl each of these bones more firmly in their place. E c the assistance, however, of the moveable intervenir. it cartilage, the clavicle can, at this joint, be raised < i? depressed, and moved backwards and forwards s much, as that the external end, which is at a grei v distance from that axis, enjoys very conspicuous mi n tions. The articulation of the exterior end of tl clavicle shall be considered after the description i ti- the scapula. StateBirth. at theirThe parts clavicles ; nor ofhave infants they areany not epiphyses deficient at intheir any es « tc othertremities such joined long afterwardsbones have, towhich their preservesbodies, as theimoj tc«.n from being bended too much, and from the danger < » any unossified parts being separated by the fore i Uses. whichThe pulls uses theof the arm clavicles forwards. are, to keep the scapulm and consequently the superior extremities, from fal ing in and forwards upon the thorax; by whic n as in most quadrupeds, the motion of the arms wou [». be much confined, and the breast made too narrw f The clavicles likewise afford origin to several musck p and a defence to large vessels. From the situation, figure, and use of the claviclt ; it is evident that they are much exposed to fracture) that their broken parts most generally go past ea( other; and that they are with difficulty kept in theiij place afterwards. OP THE SKELETON. Scapula, or shoulder-blade*, is the triangular bone Scapula. iiated on the outside of the ribs, with its longest e called its base, towards the spinal processes of the 'tebroe, and with the angle at the upper part of this e about three inches, and the lower angle at a ater distance from these processes. The back-part t the scapula has nothing but the thin ends of the ratus anticus major and subscapularis muscles be- i >en it and the ribs ; but as this bone advances for- ds, its distance from the ribs increases. The upper • shortest side, called the superior costa of the sca- a, is nearly horizontal, and parallel to the second The lower side, which is named the inferior costa, xtended obliquely from the third to the eighth rib. : situation of this bone, here described, is when pie are sitting or standing in a state of inactivity, .. allowing the members to remain in the most na- 1 easy posture. The inferior angle of the scapula j ;ry acute ; the upper one is near to a right angle; i what is called the anterior, does not deserve the e, for the two sides do not meet to form an angle, body of this bone is concave towards the ribs, ■ convex behind, where it has the name of dorsum\. je processes are generally reckoned to proceed from , scapula. The first is the large spine that rises from . onvex surface behind, and divides it unequally. , second process stands out from the fore-part of ipper side,- and, from its imaginary resemblance tow’s beak, is named coracoides ||. The third pro- is the whole thick bulbous fore-part of the bone. ; ‘ter thus naming the several constituent parts of capula, the particular description will be more , j understood. ie base, which is tipped with cartilage in a young Base, ct, is not all straight: For above the spine, it Bobliquely forwards to the superior angle; that , ttt might not be too protuberant backwards, and so jSurXar*,dpi, spatula, iavvarw*, ala, humerus, latitude clypeus, humeri, scutum scoptulum thoracis, vel sutulum tip nAiar. z. of the|| sternalAnchoroides, or central sigmoides, surface. digitalis, E. ancistroideg. 170 OF THE SKELETON. bruise the muscles and teguments: Into the oblh t space the musculus patientice * is inserted. At the r L of the spine, on the back-part of the base, a trian- L lar plain surface is formed, by the pressure of the loi t fibres of the trapezius. Below this the edge of i scapula is scabrous, for the insertion of the serr4 major anticus and rhomboid muscles. Inferior The back-part of the inferior angle is made smo p Costa. by the latissimus dorsi passing over it. This mus ,j also alters the direction of the inferior costa some v j forwards from this angle; and so far it is flatted j hind by the origin of the teres major. As the infei ; costa advances forwards, it is of considerable thi x ness, is slightly hollowed and made smooth behind the teres minor, while it has a fossa formed in it ]', low by part of the subscapularis; and between the ! . a ridge with a small depression appears, where j l longus extensor cubiti + has its origin. Superior The superior costa is very thin ; and near its fa . Costa. part there is a semilunar niche, from one end of wb to the other a ligament is stretched; and someti| . the bone is continued, to form one, or sometimes | i holes for the passage of the scapular blood-vessels | tn nerves. Immediately behind this semilunar cavity ^ coraco-hyoid muscle has its rise. From the nich< j, the termination of the fossa for the teres minor, If scapula is narrower than any where else, and sup] the third process. This part has the name of cet Dorsum. The whole dorsum of the scapula is always sai< be convex; but, by reason of the raised edges surround it, it is divided into two cavities by the s which is stretched from behind forwards, much n< to the superior than to the inferior costa. The < above the spine is really concave where the supr natus muscle is lodged ; while the surface of this below the spine, on which the irfra spinatus n is placed, is convex, except a fossa that runs at; side of the inferior costa. Internal.surface. The internal or anterior X surface of this b< * Levator scapulae. Alb. E. Jf LongSternal head or central.of the Triceps E. brachii. Alb. E. OF THE SKELETON. 171 »llow, except in the part above the spine, which is 'nvex. The subscapularis muscle is extended over ! is surface, where it forms several ridges and inter- ediate depressions, commonly mistaken for prints the ribs; they point out the interstices of the bun- es of fibres of which the subscapularis muscle is mposed (a). The spine* rises small at the base of the scapula, Spine, d becomes higher and broader as it advances for- !irds. On the sides it is unequally hollowed and i ooked, by the actions of the adjacent muscles. Its I Ige t is divided into two rough flat surfaces : Into f e upper one, the trapezius muscle is inserted; and e lower one has part of the deltoid fixed to it. The i of the spine, called acromion\, or top of the shoul- r, is broad and flat, and is sometimes joined to the ine only by a cartilage (6). The anterior edge of the romion is flat, smooth, and covered with a cartilage, its articulation with the external end of the clavi- and it is hollowed below, to allow a passage to infra and supra spinati muscles, and free motion the os humeri. The coracoid § process is crooked, with its point Coracoid lining forwards; so that a hollow is left at the lower process, e of its root, for the passage of the infra-scapular is scle. The end of this process is marked with three in surfaces. Into the internal, the serratus miner icus is inserted: From the external, one head of the eps flexor cubiti rises ; and from the lower one, the aco-brachialis has its origin. At the upper part of root of this process, immediately before the semi- ir cavity, appears a smooth tubercle, where a liga- it from the clavicle is fixed. From all the exter- side of this coracoid apophyse, a broad ligament s out, which becomes narrower where it is fixed to [) Winslow, Memoires de 1’acad. des sciences, 1722. Pterigium, crista.uftorXarut, eminentia scapulanim. 'Hiroi/jusarmus, xyxugeuins,rostrum procinum, processus digitalis.acromii os, sum. ■)’AyeujatiJrjj, Sue, Trad, fflypauSns,d’osteol. p. rostriformis. 160. 172 OF THE SKELETON. the acromion. The sharp pain, violent inflammati and tedious cure of contusions in this part, are probal owing to these tendons and ligaments being hurt. cess.Third pro- duced.From theThe cervix fore-part scapulae of this the is formedthird process into a glenis p cavity*, which is of the shape of the longitudinal s tion of an egg, being broad below and narrow abo Between the brims of this hollow and the fore-parl b the root of the spine, a large sinuosity is left for <* transmission of the supra and infra-spinati muscL and on the upper-part of these brims we may rem; *, a smooth surface, where the second head of the bic> ti fiexor cubiti has its origin. The root of the superci - is rough all round, for the firmer adhesion of the ci ’ * sular ligament of the articulation, and of the cartil; * which is placed on these brims, where it is thick, 1 Sa becomes very thin as it is continued towards the m| ;■ die of the cavity, which it lines all over. The medullary vessels enter the scapula near i u stance. baseThe of substancethe spine. of the scapula, as in all other ' flat bones, is cellular, but of an unequal thicl for the neck and third process are thick and si The inferior cotta, spine, and coracoid process, i \ a middle thickness; and the body is so pressed 1 Connexion. muscles,The scapula as to becomeand clavicle thin and are diaphanous.joined by plain faces, tipped with cartilage t; by which neither is allowed any considerable motion, being tightlj down by the common capsular ligament, and very strong one which proceeds from the coracoic cess ; but divides into two before it is fixed int clavicle, with such a direction, as either canallov bone to have a small rotation, in which its posteMlIi. edge turns more backwards, while the anterior ripji farther forwards; or it can yield to the fore-partfi: the scapula moving downwards, while the back-jft. of it is drawn upwards ; in both which cases, the OtL; long smooth articulated surfaces of the clavicle i • scapula are not in the same plan, but stand a litt •J-* wpoxiruXis.Acromion, xnruuXtit, clausurae. OF THE SKELETON. 173 msversely, or across each other, and thereby pre- rve this joint from luxations, to which it would be bject, if either of the bones was to move on the other j rpendicularly up and down, without any rotation, i metimes a moveable ligamentous cartilage is found this joint; otherwhiles such a cartilage is interposed i ly at the anterior half of it; and in some old sub- ;:ts I have found a sesamoid bone here (a). The ipula is connected to the head, os hyaides, vertebrce, is, and arm bone, by muscles, that have one end tened to these bones, and the other to the scapula, lich can move it upwards, downwards, backwards, ; forwards; by the quick succession of these motions, ’.j whole body is carried in a circle. But being also en moved as upon an axis perpendicular to its plane, j circumference turns in a circle whose centre is this is (b). Whichever of these motions it performs, it . rays carries the outer end of the clavicle and the i n along with it. The glenoid cavity of this bone ipeives the os humeri, which plays in it as a ball in a Jpket, as will be explained more hereafter. |The use of the scapula is, to serve as 0. fulcrum to Uses. arm; and, by altering its position on different oc- liions, to allow always the head of the os humeri a |;ht situated socket to move in ; and thereby to as- t and to enlarge greatly the motions of the superior remity, and to afford the muscles which rise from it ire advantageous actions, by altering their direc- .1 ns to the bone which they are to move. This bone j 0 serves to defend the back-part of the thorax, and I >ften employed to sustain weights, or to resist for- i, too great for the arm to bear, i The base, acromion, caracoid process, and head of State at 5 scapula, are all in a cartilaginous state at birth ; Birth, i i the first three are joined as epiphyses; while the " \ id, with the glenoid cavity, is not formed into a dis- 1 ct separate bone, but is gradually produced by the i ification of the body of this bone being continued 1 wards. ' i• ' a)b) Jac.See Winslow,Sylv. Isagog. Memoires anat. lib.de 1’acad.I. cap. des2. sciences, 1726. I 3 J. 174 OP THE SKELETON. The Arm has only one bone, best known by tl Latin name of os humeri* ; which is long, round, ar ' nearly straight. Upper or The upper + end of this bone X is formed into a larg 1 proximal round smooth head, whose middle point is not in end. straight line with the axis of the bone, but stands ol 1 liquely backwards from it. The extent of the head »!1■ distinguished by a circular fossa surrounding its bas ’ where the head is united to the bone, and the capsula , -: ligament of the joint is fixed. Below the fore-part • "- its base two tubercles stand out: the smaller, whic B^ is situated most to the inside §, has the tendon of tl: subscapularis muscle inserted into it. The larger moi i;< fl external || protuberance is divided, at its upper par fa into three smooth plain surfaces ; into the anterior » fa which, the musculus supra-spinatus; into the middl or largest, the infraspinatus; into the one behind, th 11 teres minor, is inserted. Between these two tuberclei fc exactly in the fore-part IT of the bone, a deep long foss t'i is formed, for lodging the tendinous head of the bicep C- fiexorcubili; which, after passing, in a manner pecu lf ’ liar to itself, through the cavity of the articulation, 1 fa1 tied down by a tendinous sheath extended across th fossa; in which, and in the neighbouring tuberclei i are several remarkable holes, which are penetrated b; : the tendinous and ligamentous fibres, and by vessel! ^ On each side of this fossa, as it descends in the os ha meri, a rough ridge, gently flatted in the middle, run! : from the roots of the tubercles. The tendon of thi a pectoral muscle is fixed into the interior of these ridge fj and the latissimus dorsi, and teres major, are inserted ti into the internal ridge. A little behind the lower ene *f Acrocolium.A*jaX/«, ipxivn, .is < brachii, armi fadjutorium, Proximal. parvuiE. chium,§ Most canna ulnad. brachii. In the description here given of the humeri^ dulousthe limb with is supposed the palm to oflie theviewed hand in directedthe supine forwards. position, orIn pelthis] positionthose towards those partsthe ulna that internal; look towards those thetowards radius the are palm external:" ai rior;|| Most and thoseradial. towards E. the elbow posterior.51 Thenal E. side. OP THE SKELETON. 175 J' this last, another rough ridge may be observed, ;; here the coraco-brachialisis inserted. From theback- irt of the root of the largest tubercle a ridge also is mtinued, from which the brevis extensor cubiti* rises. 1 his bone is flatted on the inside, about its middle, by le belly of the biceps flexor cubiti. In the middle of lis plain surface, the entry of the medullary artery is ;|!en slanting obliquely downwards. At the fore-side f this plane the bone rises in a sort of ridge, which is 1 mgh, and often has a great many small holes in it, ; here the tendon of the strong deltoid muscle is in- 1 :rted ; on each side of which the bone is smooth and , it, where the brachieus internus rises. The exterior * ,' these two flat surfaces is the larger; behind it a su- J srficial spiral channel, formed by the muscular nerve 1 id the vessels that accompany it, runs from behind j rwards and downwards. The body of the os humeri S flatted behind by the extensors of the fore-arm. I Tear the lower end of this bone, a large sharp ridge , extended on its outside, from which the musculus ipinator radii longus, and the longest head of the ex- nsor carpi radialis-\, rise. Opposite to this, there is lother small ridge, to which the aponeuretic tendon, mt gives origin to the fibres of the internal and external Vachiei muscles, is fixed; and from a little depression ill the fore-side of it, the pronator radii teres rises. | The body of the os humeri becomes gradually broad- distalLower end or ,|r towards the lower J end, where it has several pro- - isses; at the roots of which, there is a cavity before, id another behind. || The anterior is divided by a g dge into two; the external, which is the least, re- 1 fives the end of the radius; and the internal receives ■ iie coronoid process of the ulna in the flexions of the •5 >re-arm, while the posterior deep triangular cavity j [dges the olecranon in the extensions of that member. 8 'he bone betwixt these two cavities is pressed so thin t y the processes of the ulna, as to appear diaphanous » 1 several subjects. The sides of the posterior cavity ' * * Short head of the Triceps brachii. Alb. E. |j -f§ Distal.Radialis externusE- longior.|| (ixipJut.Alb. E. 176 OF THE SKELETON. are stretched out into two processes, one on each sid These are called condyles; from each of which a stroi r ligament goes out to the bones of the fore-arm. T] t external * condyle, which has an oblique direction ah ; forwards in respect of the internal f, when the arm b> in the most natural posture {a), is equally broad, an !: has an obtuse smooth head rising from it forward Bn i From the rough part of the condyle, the inferior hea of the bicornis\., the extensor digitorum commutiis, ei i u tensor carpi ulnar is §, anconeus, and some part of the si a pinator radii brevis, take their rise; and on the smooti te? head the upper end of the radius plays. Immediate! . on the outside of this, there is a sinuosity made by th i t shorter head of the bicornis muscle, upon which tli i •muscular nerve is placed. The internal condyle is mor u pointed and protuberant than the external, to give at! Hi gin to some part of the flexor carpi radialis\\, pronalw «): radii teres, palmaris longus,Jlexor digitorum sublimii t: and ^exor carpi ulnari&.% Between the two condyle^ i* is the trochlea or pulley, which consists of two lateral « protuberances, and a middle cavity, that are smootH and covered with cartilage. When the fore-arm is extended, the tendon of the internal brachieus musclj w is lodged in the fore-part of the cavity of this pulley! 1ta The external protuberance, which is less than the I1 other, has a sharp edge behind; but forwards, this ridge is obtuse, and separated from the little head, al-| ready described, only by a small fossa, in which theil joined edges of the ulna and radius move. The intetfj1 nal protuberance of the pulley is largest and highest^ and therefore in the motions of the ulna upon it, thsi bone would be inclined outwards, were it not supporM ed by the radius on that side. Between this internaf protuberance and condyle may be remarked a sinuosity where the ulnar nerve passes. The substance and the internal structure of the *(a) Radial. Winslow, E. Memoires de 1’acad.f Ulnar. des sciences, E. 1722. J§ UlnarisRadialis externus.externus. Alb.Alb. E.— || RadialisUlnaris intemus.intemus. Alb.Alb. E.E. OF THE SKELETON. 177 xeri is the same, and disposed in the same way, as ther long bones. ?he round head at the upper end of this bone is ar- Connexion, lated with the glenoid cavity of the scapula; which ig superficial, and having long ligaments, allows arm a free and extensive motion. These ligaments however considerably strong; for, besides the mon capsular, the tendons of the muscles perform office, and have been described under the name of )\\ments. Then the acromion and coracoid process, m the strong broad ligaments stretched betwixt in, secure the articulation above, where the great- ijand most frequent force is applied to thrust the Ml of the bone out of its place. It is true that there pt nearly so strong a defence at the lower part of iarticulation ; but in the ordinary postures of the ,ik that of the is, body,so long there as it cannotis at an beacute any angle force with applied the ris place to occasion a luxation, since the joint is ected so well above. he motions which the arm enjoys by this articula- Motions. , are to every side ; and by the succession of these Tent motions a circle may be described. Besides ffi, the bone performs a small rotation round its axis. But though this can be performed with round head in all positions; yet as these vary, the its upon the body of the bone are very different. , if the middle of the head be the centre of rotation, is when the arm hangs down by the side, the body le bone is moved only forwards and backwards; use the axis of motion of the head is nearly at t angles with the length of the bone faj ; where- vhen the arm is raised to right angles with the k of the body, the centre of motion, and the axis lie bone, come to be in the same straight line ; and iiefore the body of the os humeri performs the same mon with its head. Though the motions of the arm 111 to be very extensive, yet the larger share of them Winds■ on the motion of the scapula. The lower end ome os humeri is articulated with the bones of the (a) Hippocrat. de articul. § 1. I! 178 ON THE SKELETON. fore-arm, and carries them with it in all its motioi! but serves as a base on which they perform the motio ’1: peculiar to themselves; as shall be described aft< wards. ! Birth.State at new-bornBoth the infant, ends ofand this the bonelarge headare cartilaginouswith the two ir1 1'*' bercles, and the trochlea with the two condyles, becoi p epiphyses before they are united to the body of the boi Fore Ann. ulnaf he and Fore-arm radius; whose t consists situation, of two in longrespect bones, of eat 1 other, is oblique in the least straining or most natu! posture; that is, the ulna is not directly behind, ri : on the outside of the radius, but in a middle situath . between these two, and the radius crosses it. The I tuation, however, of these two bones, and of all 4 other bones of the superior extremity that are not y described, is frequently altered; and therefore, to shE 1 therepetitions, remaining I desireaccount it mayof the now superior be remarked, extremity, that, 1 uj i, derstand by the term of posterior that part which isi1 the same direction with the back of the hand ; by at. terior, that answering to the palm ; by internal, thi • on the same side with the thumb ; by external, the sic nearest to the little finger; supposing the hand alwaj i to be in a middle position between pronation an Ulna. supination.Ulna X, so named from its being used as a measufl v is the longest of the two bones of the fore-arm, and si Upper ei d. tuated^t the on upperthe outside end of of the the ulna radius. are two processes.! The posterior § is the larger, and formed like a hooH] whose concave surface moves up on the pulley of the*: humeri, and is called o/ecra«on ||, or top of the cubit.jl« The convex back part of it is rough where the /o»gl ‘ brevis, H and brachius externus, are inserted. The ole. cranon makes it unnecessary that the tendons of tht extensor muscle should pass over the end of the os huj * See Barcl. Muscul. Mot. p. 381. + Cubitus, rw,rrrixvi, I OP THE SKELETON. in the ligament of the articulation of the wrist is fixe On the internal side of this bone, where it is contigi ous to the os lunare, it is smooth and slightly concaV Its lower surface, where it is contiguous to the os in ciforme, is oblong, somewhat spiral, and concav Near the middle of its anterior surface a circular plaj appears, where the os pisiforme is sustained. forme.Os Pisi- lar Osplane, pisiforme or slighly * is almost hollow spherical, surface, exceptwhich isone coven circi with cartilage for its motion on the cuneiform boi i from which its whole rough body is prominent fa ' wards into the palm ; having the tendon of the flex , carpi ulnaris, and a ligament from the styloid procal , of the ulna, fixed to its upper part; the transverse gament of the wrist is connected to its internal side; |ji, gaments extended to the unciform bone, and to theX metacarpi of the little finger, are attached to its lowfl ' part; the abductor minimi digiti has its origin from |l, fore-part; and, at the internal side of it, a small d| pression is formed, for the passge of the ulnar nervtf ; Trapezium. back-part,Trapezium-f from has which four unequalit has got sides its andname. angles Abo*/ in* !' its surface is smooth, slightly hollowed, and semiqBI i cular, for its conjunction with the os scaphoides. I| external side is an oblong concave square, for receu ing the following bone. The inferior surface is fortS " into a pulley ; the two protuberant sides of which »7 external and internal. On this pulley the first bqi| of the thumb is moved. At the external side of external protuberance, a small oblong smooth surflUj is formed by the os metacarpi indicis. The fore-f|t| of the trapezium is prominent in the palm, and, nfll to the external side, has a sinuosity in it, where llj tendon of the flexor carpi radialis is lodged; onHj ligamentous sheath of which the tendon of the /fcw tertii internodii pollicis plays: And still more extB" nally the bone is scabrous, where the transverse ligfl ment of the wrist is connected, the abductor and/efl primi internodii pollicis have their origin, and lig* ments go out to the first bone of the thumb. +* Oartilaginosum,Os cubiforroe, trapezoides, subrotundum, multangulum rectum. majus. rH OP THE SKELETON. 187 Ds trapezoides *, so called from the irregular quad- Os Trape- gular figure of its back-part, is the smallest bone zoides. the wrist, except the pisiforme. The figure of it is irregular cube. It has a small hollow surface ve, by which it joins the scaphoides ; a long con- one internally, where it is contiguous to the tra- a small external one, for its conjunction with os magnum; and an inferior convex surface, the es of which are however so raised before and be- 1, that a sort of pulley is formed, where it sustains os metacarpi indicis. )s magnum f, so called because it is the largest bone Os Mag- ,he carpus, is oblong, having four quadrangularnum- s, with a round upper X end, and a triangular plain below §.—The round head is divided by a small ig, opposite to the connexion of the os scaphoides lunare, which together form the cavity for receiv- it—On the inside a short plain surface joins the agnum to the trapezoides.—On the outside is a long }w concave surface, where it is contiguous to the iciforme. The lower end, which sustains the me- pal bone of the middle finger, is triangular, slight- ulowed, and farther advanced on the internal side on the external, having a considerable oblong ession made on the advanced inside by the meta- al bone of the fore finger; and generally there is all mark of the os metacarpi digiti annularis on its :nal side. r unciforme || has got its name from a thin broad Os Unci- ;ss that stands out from it forwards into the palm,/orms. is hollow on its inside, for affording passage to the mis of the flexors of the fingers. To this process is fixed the transverse ligament that binds down defends these tendons ; and the flexor and abduc- inscles of the little finger have part of their origin it. The upper plain surface is small, convex, oined with the os lunare :—The internal side is and slightly convex, adapted to the contiguous 'rapezium, multangulum minus, XUjpi Hi•istad.laximum E. capitatum. $|| Proximal.Cuneiforme. E. 188 OF THE SKELETON. os magnum :—The external surface is oblique, and: regulary convex, to be articulated with the cuneifoi bone : The lower end is divided into two concave st faces ; the external is joined with the metacarpal bo of the little finger, and the internal is fitted to t metacarpal bone of the ring-finger. L In the description of the preceding eight bones, have mentioned only those plain surfaces covered wi If cartilage, by which "they are articulated to each othi [r or to some other bones, except in some few caa f where something extraordinary was to be observe ‘ and I have designedly omitted the other rough sv faces, lest, by crowding too many words in the d • scription of such small bones, the whole should be u 11 intelligible: But these scabrous parts of the bor 1 may easily beunderstood, after mentioning their figtu if it be observed, that they are generally found on f towards the back or palm of the hand; that they a 1 all plain, larger behind than before ; and that th receive the different ligaments, by which they are ca nected either to neighbouring bones, or to one anothg ? for these ligaments cover all the bones, and are so I curately applied to them, that, at first view, the wh4 ' carpus of a recent subject appears one smooth bone ( V Figurethe Carpus, of theAs figure the surfacesof the whole of these conjoined bones must are belargest convex behii th< A and concave before; which concavity is still more " creased by the os pisiforme, and process of the os mill forme, standing forwards on one side, as the trapezm. does on the other : And the bones are securely kajl in this form, by the broad strong transverse ligamj connected to these parts of them that stand prominl into the palm of the hand. The convexity beta renders the whole fabric stronger where it is exposed to injuries ; and the larger anterior hollo necessary for a safe passage to the numerous v ™ nerves, and tendons of the fingers. The substance of these bones is spongy and ce)| lar, but strong in respect of their hulk. tion(a) of Galen these deligaments, usu part. seelib. Weitbrecht, 2. cap. 8. ForSyndesmolog. a particular p. descao OF THE SKELETON. The first three bones of the carpus make an oblong Motions, ad, by which they are articulated with the cavity the lower ends of the bones of the fore-arm, so as allow motion to all sides, and, by a quick succes- m of these motions, they may be moved in a circle, it as the joint is oblong, and therefore the two di- i insions are unequal, no motion is allowed to the | rpus round its axis, except what it has in the pro- ! tion and supination along with the radius.—The : dculation of the three first bones of the superior row, th the bones of the inferior, is such as allows of mo- , m, especially backwards and forwards; to the secu- | y and easiness of which the reception of the os mag- in into the cavity formed by the scaphoids and tare contributes considerably : And the greatest mber of the muscles that serve for the motion of 2 wrist on the radius, being inserted beyond the ijunction of the first row of bones with the second, ; equally on this articulation as they do on the for- :r; but the joint formed with the radius being the ist easily moved, the first effect of these muscles is it; and the second row of the carpus is moved af- wards. By this means a larger motion of the wrist illowed, than otherwise it could have had safely; , if as large motion had been given to one joint, the y\e of flexion would have been very acute, and the aments must have been longer than was consistent ;h the firmness and security of the joint. The other iculations of the bones here being by nearly plain faces, scarcely allow of any more motion, because the strong connecting ligaments, than to yield a le,L to andrender so elude the back the offorce the ofwrist any aexternal little more power flat, ; the palm more hollow, on proper occasions. The iculations of the thumb and metacarpal bones shall examined afterwards *. The uses of the carpus are to serve as a base to the Uses, id, to protect its tendons, and to afford it a free ;e motion. \.ll the bones of the carpus are in a cartilaginous State at ;e at the time of birth. Birth. * See Barcl. Muscul. Mot. p. 400. E. 190 OF THE SKELETON. On account of the many tendons that pass upon lower end of the fore-arm and the carpus, and of t numerous ligaments of these tendons and of the bonl r. which have lubricating liquors supplied to thenij t pain of sprains here is acute, the parts take long til to recover their tone, and their swellings are v< Metacarpus. obstinate.Metacabpus* consists of four bones which susts i. the fingers. Each bone is long and round, with r ends larger than its body. The upper f end, whi some call the base, is flat and oblong, without any cfi siderable head or cavity; hut it is however somewl v hollowed, for the articulation with the carpus: It!. made flat and smooth on the sides where these hoc . are contiguous to each other. Their bodies are flatt „ on their back-part by the tendons of the extensors . the fingers. The anterior surface of these bodies ii little concave, especially in their middle; along whi ; a sharp ridge stands out, which separates the mus& interossei placed on each side of these bones, which | j' there made flat and plain by these muscles. " Their lower J ends are raised into large obh smooth heads, whose greatest extent is forwards " the axis of the bone At the fore-part of each sii the root of each of these heads, one or two tuhei stand out, for fixing the ligaments that go from metacarpal hone to another, to preserve them from ing drawn asunder.—Round the heads a rough i may be remarked, for the capsular ligaments of first joints of the fingers to be fixed to ; and both of these heads are flat, by pressing on each other. The substance of the metacarpal bones is the State at withAt thatthe timeof all oflong birth, bones. these bones are cartilagii Birth. at; both ends, which afterwards become epiphyses. Connexion. carpiThe and metacarpal to each other bones by are nearly joined plain above surfaces. to the T1 connexions are not fit for large motions. 1 he art lation of their round heads at the lower ends with th * Kn/j, cntot avbn'-oi iv, postbrachiale, pcfl palma,■j- ProximaJ. pecten. E. $ Distal. E. ' OF THE SKELETON. 191 4vities of the first bones of the fingers, is to be taken jptice of hereafter. The concavity on the fore-part of these metacarpal >nes, and their placing their bases on the arched car- ■, cause them to form a hollow in the palm of the .nd, which is often useful to us. The spaces between em lodge muscles, and their small motion makes em fit supporters for the fingers to play on. Though the ossa metacarpi so far agree, yet they Differen. ay be distinguished from each other by the follow- ces. g marks. The os metacarpi indicis is generally the longest.— 3 base, which is articulated with the os trapezoides, hollow in the middle. The small ridge on the in- nal side of this oblong cavity is smaller than the e opposite to it, and is made flat on the side by the ipezium. The exterior ridge is also smooth, and t on the outside, for its conjunction with the os mag- Im; immediately below which a semicircular smooth [t surface shews the articulation of this to the second ‘tacarpal bone. The back part of this base is flat- 1, where the long head of the extensor carpi radia- ~ is inserted; and its fore-part is prominent, where . tendon of the jlexor carpi radiahs f is fixed. The ternal side of the body of this bone is more hollow- by the action of the muscles, than the internal, e tubercle at the internal root of its head is larger n the external. Its base is so firmly fixed to the e it is connected with, that it has no motion. Os metacarj)i medii digiti is generally the second in “igth ; but it is often as long as the former ; some- es it is longer ; and frequently it appears to equal first only by the os magnum being further advan- downwards than any other bone of the wrist. Its e is a broad superficial cavity, slanting outwards ; internal posterior angle of which is so prominent to have the appearance of a process. The internal e of this base is made plain in the same way as the ;ernal side of the former bone, while its external side two hollow circular surfaces, for joining the third iialis externus. Alb. E. t Radialis interims. Alb. E. 192 OF THE SKELETON. metacarpal bone, and between these surfaces there 5 a rough fossa, for the adhesion of a ligament, a 1: lodging mucilaginous glands. The shorter head of t ; bicornis * is inserted into the back-part of this ba; The two sides of this bone are almost equally flatte f only the ridge on the fore-part of the body inclir kt1 r outwards. The tubercles at the fore-part of the rc i of the head are equal. The motion of this bone is ve it little more than the first metacarpal one has; ai 1 therefore these two firmly resist bodies pressed agair i them by the thumb, or fingers, or both. li. Os metacarpi digiti annularis is shorter than the s cond metacarpal bone. Its base is semicircular a; convex, for its conjunction with the os unciforme. C : its internal side are two smooth convexities, and , middleyossu, adapted to the second metacarpal bon The external side has a triangular smooth concave su face to join it with the fourth one. The anterior ridj of its body is situated more to the out, than to the i. side. The tubercles near the head are equal. T] motion of this third metacarpal bone is greater thj the motion of the second. Os metacarpi minimi digiti is the smallest and shar est. Its base is irregularly convex, and rises slanti outward. Its internal side is exactly adapted to tl third metacarpal bone. The external has no smo< surface, because it is not contiguous to any other bon but it is prominent where the extensor carpi ulnaris inserted. As \hi& metacarpal bone is furnished witl proper moving muscle, has the plainest articulate is most loosely connected, and least confined, it not 01 enjoys a much larger motion than any of the rest, \ draws the third bone with it, when the palm of hand is to be made hollow by its advancement forwai and by the prominence of the thumb oppisite to it. The Thumb and four Fingers are each compos of three long bones. The Thumb f is situated obliquely in respect< the fingers, neither directly opposite to them, nor 1 ; Radialis externus brevior.magnus digitus,Alb. promanus.E. OF THE SKELETON. 193 same plane with them. All its bones are much 4 :ker and stronger in proportion to their length, n the bones of the fingers; which was extremely ne- sary, since the thumb counteracts all the fingers, ’he first bone * of the thumb has its base adapted jhe double pulley of the trapezium: For, in view- it from one side to the other, it appears convex in ; ! middle : but when considered from behind for- ! ds, it is concave there. The edge at the fore-part tiis base is produced farther than any other part 1 i round the back-part of the base a rough fossa i 1 be seen, for the connexion of the ligaments of this t. The body and head of this bone are of the same I e as the ossa metacarpi; only that the body is ■' ter, and the head flatter, with the tubercles at the '4he -part articulation of its root of larger. the upper end of this bone is un- - jjjmon ; for though it has protuberances and de~ sions adapted to the double pulley of the trapezium, t enjoys a circular motion, like the joints where a j d head of one bone plays in the orbicular socket mther; only it is somewhat more confined and expeditious, but stronger and more secure, than joints generally are. tis bone in children is in the same state with the carpal bones. le second bone + of the thumb has a large base id into an oblong cavity, whose greatest length m one side to the other. Round it several tuber- iay be remarked, for the insertion of the ligaments, ady is convex, or a half-round behind; but flat . e, for lodging the tendon of the long Jlexor of \ umb, which is tied down by ligamentous sheaths < re fixed on each side to the angle at the edge of at surface. The lower end of this second bone has i ateral round protuberances, and a middle cavity, . ; 2 greatest extent of smooth surface is forwards. ; ?rimum internodium, or metacarpal bone of the thumb. I1 ecundumE. internodium, proximal phalan*. E. 194 OF THE SKELETON. The articulation and motion of the upper end this second bone is as singular as that of the form For its cavity being joined to the round head of first bone, it would seem at first view to enjoy mot . in all directions ; yet, because of the strength of f lateral ligaments, oblong figure of the joint its and mobility of the first joint, it allows only flex p, and extension ; and these are generally most confin The third bone* of the thumb is the smallest, w a larger base, whose greatest extent is from one side the other. This base is formed into two cavities an middle protuberance, to be adapted to the pulley}: the former bone. Its body is rounded behind : bu flatter than in the former bone, for sustaining the n t It is flat and rough before, by the insertion of j i. flexor tertii internodii. This bone becomes gradua smaller, till near the lower end, where it is a little larged, and has an oval scabrous edge. The motion of this third bone is confined to flex and extension. Phalanges The orderly disposition of the bones of the flt of the fin- into three rows, has made them generally obtain) gen. name of three phalanges +. All of them have ' round convex surfaces, covered with an aponew formed by the tendons of the extensors, lumbria and interossei, and placed directly backwards jJ their greater strength, and their flat concave part is) wards ||, for taking hold more surely, and for lodj the tendons of the flexor muscles. The ligament keeping down these tendons are fixed to the a that are between the convex and concave sides. The bones of the first phcrlanx § of the fingers an! proximalFirst or to the description of the second bone of the thu phalanx. only that the cavity in their base is not so obli nor is their motion on the metacarpal bones so confined ; for they can be moved laterally or * Tertium iqternodium, distal phalanx. E. culi.j* Scytalida, internodia, scuticula, agmina, acies, condyli, | J§ Anconad. E.Proximal phalanx. E. [] Thenad. 'tj 1 r, but have no rotation, or a very small degree of 4 onnd their axis. 1 oth the ends of the first phalanx are in a cartila- us state at birth ; and the upper one is afterwards ' ed in form of an epiphyse. ! he second bone * of the fingers has its base form- Second or i ito two lateral cavities, and a middle protube-m^,e : e; while the lower end has two lateral protube- p aanx> i es and a middle cavity; therefore it is joined at 4 ends in the same manner, which none of the i of the thumb are. is bone is in the same condition with the former t lildren. i tie third bone + differs in nothing from the des- Third or i ion of the third bone of the thumb, excepting in 3 '' I 198 OF THE SKELETON. qmdratus is inserted. In the deep hollow, at thd ternal upper side of this ridge, the obturator extei is implanted. More internally, a conoid process, < ed trochanter minor *, rises from the insertion of musculus psoas, and iliacus internus ; and the pecth is implanted into a rough hollow below its inte root. The muscles inserted into these two proces being the principal instruments of the rotatory mo of the thigh, have occasioned the name of trochan to the processes. The tendons that are fixed into [®? pass over the great trochanter, cause bruises by i on this part to be attended with great pain and w< ^ ness of the limb, which generally remain long. Body. The body of the os femoris is convex on the f . “ 202 OF THE SKELETON. bone moves. The circumference of these cavities i rough and unequal for the firm connexion of the lij 5 ments of the joint Immediately below the edge its back part, two rough flatted protuberances sta 1 out. Into the internal*, the tendon of the semimt *■ branosus muscle is inserted ; and a part of the cr ^ ligament is fixed to the external +. On the outs *■ of this last tubercle, a smooth slightly-hollowed sfl • Body. faceBelow is formed the fore-part by the action of the of upper the popl end teusof themuscl til ' rises a considerable rough protuberance J, to wh the strong tendinous ligament of the rotula is fix On the internal side of this, there is a broad scabrJi1' slightly hollowed surface, to which the internal law1 ligament of the joint, the aponeurosis of the mw/m* 11^ ternus, and the tendons of the seminervosus, graciUi and sartorius, are fixed. The lowest part of this sv1 face is therefore the place where the tibia ought to j| sawed through in an amputation, so as not to have tt| long and troublesome a stump, and, at the same timl to preserve its motions, by saving the proper musclfir Below the external edge of the upper end of the tibi\ there is a circular flat surface, covered in a recent sulj ject with cartilage, for the articulation of the Jibulnj^ between which and the anterior knob, there is a rou||t : hollow from which the tibialis anlicus, and extensor Ij11 gitorum || longus, take their origin. From the smodlr flat surface, a ridge runs obliquely downwards an! inwards, to give rise to part of the soleus, tibialis post ticus, sendi flexor digilarum longus, and insertion to thij aponeurosis of the semimembranosus which covers flr popl tens, and to some of the external fibres of thin! last named muscle. At the inside of this ridge® oblique plain surface is left, where the greatest pan* of the muscnlus popliteus is inserted. The remaining body of the tibia is triangular. The anterior angle ii mi +• Tibial. E< anterior+ tuber.Fibular. E. || It is scarcely necessary to remark, that here, and in all sue- ■ ceedingmentioned, passages the word where pedis the is Jlcxorsundeistood. and exlemorsE. of the toes or THE SKELETON. 205 jry sharp, and is commonly called the spine or shin*. ■Iiis ridge is not straight; but turns first inwards, fpi outwards, and lastly inwards again. The plain Mernal side is smooth and equal, being little subject- i to the actions of muscles ; but the external t side ji Hollowed above by the tibialis anticus, and below by A i extensor digitorum longus and extensor pollicis lon- r. The two angles behind these sides are rounded the action of the muscles; the posterior side com- ihended between them is not so broad as those al- dy mentioned, but is more oblique and flatted by i action of the tibialis posticus and Jlexor digitorum gus. Some way above the middle of the bone, the ernal angle terminates, and the bone is made round the pressure of the musculus soleus. Near to this, ; passage of the medullary vessels is seen slanting h'quely downwards. The lower end of the tibia is made hollow, but so Lower or it a small protuberance rises in the middle. The Distal end. ernal side of this cavity, which is smooth, and in a :ent subject covered with cartilage, is produced in- a considerable process, commonly called malleolus et nus ; the point of which is divided by a notch, i from it ligaments are sent out to the foot. We ght to observe here, that this internal malleolus is uated more forwards than the internal condyle of j upper end of this bone; which is necessary to be nembered in reducing a fracture of the leg (a), le external side of this end of the tibia has a rough egular semilunar cavity formed in it, for receiving : lower end of the fibula. The posterior || side has o lateral grooves, and a small middle protuberance, the internal depression, the tendons of the musculus I'alis posticus and jlexor digitorum longus are lodged ; 1 in the external, the tendon of jlexor longus pol- s plays. From the middle protuberance, ligamen- aiis sheaths go out, for tying down these tendons. i' Y' AxavSu,b'ibular. spina, E. area, linea prima tibiae, angulus acutus. |-1 : I'ibial«•!«•«*, ankle. talus, E. clavicula, clavilla interior, clavilla domes- { a)U Popliteal.Winslow, ExpositionE. anatomique, des os secs, sect. 865. K 6 204- OF THE SKELETON. The articulations and motions of the tibia shall explained, after all the three bones of the leg a scribed. Both the ends of the tibia are cartilages at birt . Birth.State it and become afterwards epiphyses. Fibula* is the small long bone, placed on i i Fibula. outside of the leg, opposite to the external angle $ the tibia ; the shape of it is irregularly triangular. Proximal The head of the Jibula has a superficial circular ( End. vity formed on its inside, which, in a recent subje is covered with cartilage, but so closely connected the tibia by ligaments, as to allow only a small m i> tion backwards and forwards. The head is protub rant and rough on its outside, where a strong roui r ligament and the musculus biceps are inserted; an below the back-part of its internal side, may be i marked a tubercle that gives rise to the strong tel dinous part of the solens muscle. Body. The body of this bone is a little crooked inwarM, and backwards t, which figure is owing to the actioil of the muscles; but is still further increased by nursil' who often hold children carelessly by the legs. Thl sharpest angle of the Jibula is forwards J on each siil of which the bone is considerably but unequally pressed by the bellies of the several muscles that rwl from, or act upon it; and, in old people, these muse®, make distinct sinuosities for themselves. The extel*| nal surface of the Jibula is depressed obliquely from- above downwards and backwards, by the two jicroiMki Its internal surface is unequally divided into two naM row longitudinal planes, by an oblique ridge extend® from the upper-part of the anterior angle, to join wipi the lower end of the internal angle. To this ridj* ' the ligaments stretched between the two bones of tl leg is connected. The anterior of the two planesl very narrow above, where the extensor longus dig®. rum and extensor longus pollicis arise from it; but is j broader below, where it has the print of the n • perone, focile minus, arundo minor, canna mi-1 lotf cruris, Tibial sura,and poplitead.radius. E. $ Rotulad. E. OF THE SKELETON. 205 alii *. The posterior plane is broad and hollow, 'ng origin to the larger share of the tibialis posti- The internal angle of this bone has a tendinous 'brane fixed to it, from which fibres of the flexor 'torum longus take their rise. The posterior sur- - of the Jibula is the plainest and smoothest, but is e flat above by the soleus, and is hollowed below the flexor pollicis longus. In the middle of this face the canal for the medullary vessels may be l slanting downwards. have taken particular notice of the entry and direc- Remarks of the medullary vessels of the large bones of the on ^ emities (a) : because, in several chirurgical cases, rgeon, who is ignorant of this, may do mischief to i y vessels, patient. Thus, for example, if these vessels are ar ed very near to their entry into the bone, or while ' i the oblique passage through it, an obstinate orrhagy may ensue ; for the arteries being con- d to the bony passage, styptics, and other like ugators, are vainly applied; compressing instru- ts can do no service, and ligatures cannot be em- ed. There seems to be a particular design in the rivance of these canals ; those in the os humeri, and Jibula, running obliquely downwards from external entry; whereas, in the radius, ulna, and ' , they slant upwards, whereby the arteries and es which are sent into these three last bones, must r a considerable reflection before they come at the 'Hi. The reason of this diversity may perhaps be, he arteries which are so smallwith in the bones as ve no strong contractile propelling force in their , and where they are not assisted by the action of noving neighbouring organ, should have, at least ir passage through the bone, a favourable descent leir liquids ; which, it is evident, they have in the nding oblique passages formed for them in the lass of bones, viz. the os humeri, tibia, and flbu- xich are generally depending; and they also most ently acquire the like advantage in the radius, and osfemoris, because the hand, in the most neusi, tertius.Osteolog. Alb. nov. disc.E. 1. p. 59. 206 OF THE SKELETON. natural posture, is higher than the elbow ; and wh| we sit or lie, the lower end of the thigh bone comes be at least as high raised as the upper. In standi| and walking, or when the arms are moved, the bl< must indeed ascend as it passes through the bones, the fore-arm and thigh; but the pressure of the imj cles then in action, on the vessels, before they enj the bones, is sufficient to compensate the disadvant of their course. This reasoning seems to be still forced, by observing, that this passage is always nej er the upper than the lower ends of these bones (< Distal end. The lower end of the fibula is extended ii spongy oblong head, on the inside of which is a vex, irregular, and frequently scabrous surface, is received by the external hollow of the tibia, ancfl firmly jointed to it by a very thin intermediate c*[ tilage and strong ligaments, that it can scarcely mov] •—Below this, Xhejibula is stretched out into a i noid process, that is smooth, covered with cartila^ its internal side, and is there contiguous to the out of the first bone of the foot, the astragalus, to se< the articulation. This process, named malleolus] /emus*, being situated farther back than the inti malleolus, and in an oblique direction, obliges ui turally to turn the fore-part of the foot outwards! At the lower internal part of this process, a spot cavity for mucilaginous glands may be remarkj from its point ligaments are extended to the aslragi os calcis, and os naviculare, bones of the foot; from its inside short strong ones go out to the ash lus. On the back-part of it a sinuosity is mat and(a) Monro, From respectingthe joint observationsthe direction of ofCharles the canal Stephans, for the laryrule: arteries That inof those long bonesbones, which we may are deduce commonly the followingin the dej runposition, from asthe the proximal humerus, or superiorthe HUa, end and of the fibula,bone towards these id thetal horizontal,or inferior; (or while other thosethan awhich depending) arc usually position, or asfrequeaj the AL proximalthe radius, end and of thethe bone. ulna, theyE. run from the distal towards I (i)• Fibular Winslow, ankle. Memoires E. de 1’Acad. des Sciences, 1722. OF THE SKELETON. 207 j e tendons of the peronei muscles When the liga- ! ;nt extended over those tendons from the one side the depression to the other is broken, stretched too ich, or made weak by a sprain, the tendons fre- rjently start forwards to the outside of the fibula. .'The conjunction of the upper end of the fibula with Connexion, s) i tibia is by plain surfaces tipped with cartilage, a 1 at its lower end the cartilage seems to glue the l a bones together, not, however, so firmly in young Sple, but that the motion at the other end of such >ng radius is very observable. In old subjects, I :n see the two bones of the leg grown together ;heir lower ends. he principal use of this bone is to afford origin Uses, insertion to muscles ; the direction of which may a little altered on proper occasions, by its upper shuffling backwards and forwards. It likewise is to make the articulation of the foot more secure firm. The ends of the tibia and Jibula being er than their middle, a space is here left, which is d up with such another ligament as I described mded between the bones of the fore-arm ; and ch is also discontinued at its upper part where tibialis anticus immediately adheres to the soleus tibialis posticus; but everywhere else it gives in to muscular fibres {a). oth the ends of this bone are cartilaginous in a State at child, and assume the form of appendices before are united to its body. otula* is the small flat bone situated at the fore- Rotula. of the joint of the knee. Its shape resembles the mon figure of the heart with its point downwards, anterior convex surface of the rotula is pierced great number of holes, into which fibres of the ig ligament that is spread over it enter. Behind, irface is smooth, covered with cartilage, and di- 1 by a middle convex ridge into two cavities, of h the externalf is largest; and both are exactly En/iukisWeitbrecht. fiuXax^s, Syndesmolog. xly-ga;, p.tmyttciTis, 156. rXavwmigoi,, patella, kgenu, scutiforme os, cartiliginosum, disciforme, ocidus 6eenu. ■ibula. E. 208 OF THE SKELETON. adapted to the pulley of the osfemoris, on which thi are placed in the most ordinary unstraining postui of the leg; but when the leg is much bended, the i tula descends far down on the condyles ; and wh< the leg is fully extended, the rotula rises higher in j upper part, than the pulley of the thigh-bone.—Tl plain smooth surface is surrounded by a rough prf minent edge, to which the capsular ligament adhert —Below, the point of the bone is scabrous, where tj strong tendinous ligament from the tubercle of tibia is fixed. The upper horizontal part of this b< is flatted and unequal, where the tendons of the tensors of the leg are inserted. The substance of the rotula is cellular, with very tl external firm plates ; but then these cells are so sm; and such a quantity of bone is employed in their fij mation, that scarcely any bone of its bulk is so stroi Besides, it is covered all over with a thick ligamt (as it was observed that this sort of bones generj is,) to connect its substance, and is moveable to eiti side; therefore it is sufficiently strong to resist the dinary actions of the large muscles that are insertf into it, or any common external force applied to it while a fixed process, such as the olecranon, would fl have been sufficient to bear the whole weight of ou bodies, which frequently falls on it, and would hr1 hindered the rotatory motion of the leg. Notwithsti ing these precautions to preserve this bone from 4 injuries, yet I have seen a transverse fracture if when, by the report of the patient, and of the pel about him, and by the want of swelling, discolouil or other mark of bruise or contusion, it was plaint- bone was broken by the violent straining effort of|th|! muscles (a). Though my patient recovered the of the joint of the knee, yet I think it reasonabjB believe, that this sort of fracture is commonly att< ed with difficulty of motion, after the broken pari the rotula are reunited ; because the callous matte probably extends itself into the cavity of the join: where it either grows to some of the parts, or make («) See Ruysch. Observ. Anat. chirurg. ob». 8. OF THE SKELETON. 209 Ii an inequality on the surface of this bone, as i not allow it to perform the^necessary motions on condyles of \hefemur (a). t the ordinary time of birth, the rotula is entirely state at ilaginous, and scarcely assumes a bony nature so Birth, i as most epiphyses do. he parts which constitute the joint of the knee be- Motions of row described, let us examine what are its motions, the Knee how performed. The two principal motions are on and extension. In the former, the leg may be ght to a very acute angle with the thigh, by the >.yles of the thigh-bones being round and made ith far backwards. In performing this, the rotula died down by the When the leg is to be aded, the rotula is drawn upwards, consequently ibia forwards, by the extensor muscles ; which by is of the protuberant joint, and of this thick bone its ligament, have in effect the chord, with which : act, fixed to the tibia at a considerable angle, Tore act with advantage ; but are restrained from ng the leg farther than to a straight line with the i, by the posterior part of the cross ligament, that »ody might be supported by a firm perpendicular nn. For at this time the thigh and leg are as moveable in a rotatory way, or to either side, as y were one continued bone. But when the joint ittle bended, the rotula is not tightly braced, and osterior ligament is relaxed; therefore this bone be moved a little to either side, or with a small '.j on in the superficial cavities of the tibia; which . ne by the motion of the external cavity back- t( s and forwards, the internal serving as a sort of b). Seeing then one part of the crow ligament lated perpendicularly, and the posterior part is i hed obliquely from the internal condyle of the outwards, that posterior part of the cross liga- | prevents the leg’s being turned at all inwards; J. t could not hinder it from turning outwards al- >ar v <: 4 ®> li - 15. cap. 22. f ’r«ji ! Vinslow,secs, § 976. Exposition anatomique du corps hutnain, traite 210 OF THE SKELETON. most round, were not that motion confined by the teral ligaments of this joint, which can yield li This rotation of the leg outwards is of good advani to us in crossing our legs, and turning our feet < wards, on several necessary occasions ; though { altogether fit this motion should not be very largd prevent frequent luxations here. While all these tions are performing, the part of the tibia that ma immediately on the condyles is only so much i within the cartilaginous rings, which, by the thickl on their outsides, make the cavities of the tibia nj horizontal, by raising their external side where ' surface of the tibia slants downwards. By this m| the motions of this joint are more equal and staj than otherwise they would have been. The cartiJa being capable of changing a little their situation, fit for doing this good office in the different moti and postures of the member, and likewise contrih to make the portions larger and quicker (a). II Diseases. On account of the very large surface of the bo forming the joint of the knee, and the many stn ligaments connecting them, luxations seldom hap] here. But these very ligaments, the aponeurosis ing over this point, the quantity of fat and mucila nous glands necessary for lubricating it, make it m subject to white-swellings, dropsies, and similar dis ders, than any other joint of the body. Foot The Foot, as well as the hand, is divided into tb parts, viz. tarsus, metatarsus, and toes: In the desd tion of which, the several surfaces shall be nan! according to their natural situation, viz. the broat the foot, shall be called superior ; the sole, infer| the side on which the great toe is, internal; tl where the little toe is, external. Tarsus. The tarsus* consists of seven spongy bones: to V the astragalus, os calcis, naviculare, cuboides, < forme externum, ctmeiforme medium, and ouneifKL internum. The astragalus is the uppermost of these bonesB: The os calcis is below the astragalus, and is considfl (a) See Barcl. Miucul. Mot. p. 433. E. * Hasw 4 OF THE SKELETON. 211 nly prominent backwards beyond the other bones to if rm the heel. The os naviculare is in the middle of i|,e internal side of the tarsus*. The os ctiboides is • <.e most external of the row of four bones at its fore- irtf. The os cuneiforme externum is placed at the sidej of the cuboid. The cuneiforme medium is be- reen the external and internal cuneiform bones, and e internal cuneiform is put at the internal side of , e foot||. 1 That the description of these bones may not be im- oderately swelled with repetition, I desire, once for 1 , to observe, that wherever a ridge is mentioned, thout a particular use assigned, a ligament is un- I rstood to be fixed to it; or where a spongy rough ii vity, depression, or fossa is remarked, without nam- 5 its use, a ligament is inserted, and mucilaginous mds are lodged; for such will occur in the details ,, I each of these bones. HThe upper part of the astragalus^ is formed into a Astragalus. jtjfge smooth headlT, which is slightly hollowed in middle ; and therefore resembles a superficial pul- lljr, by which it is fitted to the lower end of the tibia. Ipe internal side of this head is flat and smooth, to jky on the internal malleolus. The external side has Mo such a surface, but larger, for its articulation with <£ external malleolus. Round the base of this head s:re is a roughybssa ; and, immediately before the ,! id, as also below its internal smooth surface, we |i d a considerable rough cavity. The lower surface of the astragalus is divided by irregular deep rough/ossa; which at its internal end arrow,butgraduallywidens,as it stretches obliquely wards and forwards. The smooth surface**, cover- with cartilage, behind this fossa, is large, oblong, ended in the same oblique situation with the fossa 1 concave, for its conjunction with the os calcis. i DistaDistad l ofof the the astragalus, os calcis on on the the fibuiar tibial side.side of E.the foot. E. i Tibiad.Distad ofE. the naviculare on the tibial side. E. : ■ j "Arfits, talus, balistae os, malleolus, chaib, qua trio, os tessarae, .siri [icuiae, Ttr£W£or. unciforme. * * Proximal side. E. 212 OP THE SKELETON. The back-part of the edge of this cavity is produce into two sharp-pointed rough processes,between whie is a depression made by the tendon of the jiexor pott cis longus. The lower surface before \he fossa is col vex, and composed of three distinct smooth plane The long one behind, and the exterior or shortest, aj articulated with the heel-bone; while the intertoi which is the most convex of the three, rests and movi upon a cartilaginous ligament, that is continued fro( the calcaneum to the os scaphoides—- Withou t whi< ligament, the astragalus could not be sustained, bi would be pressed out of its place by the great weig it supports, and the other bones of the tarsus won be separated. Nor would a bone be fit here, becaui it must have been thicker than could conveniently 1 allowed; otherwise it would break, and would m prove such an easy bending base, to lessen the shod which is given to the body in leaping, running, &(| The fore part* of this bone is formed into a convj oblong smooth head, called by some its process, whit is received by the os naviculare. Round the root« this head, especially on the upper surface, a roug fossa may be remarked. The astragalus is articulated above to the tibia an fibula, which together form one cavity. Though,; this articulation, the bone have prominences and APPENDIX. \k OF THE MARKS OF A FEMALE SKELETON. M To finish the description of the bones, is generally 1 s conclude the osteology; but that no part of the subjei It? themay distinguishing be left untouched, marks I ofthink the maleit necessary and female to subjoi skeh isiis tons; and have chosen to illustrate them principal! t in the latter; because women having a more delicaf y constitution, and affording lodging and nourishmei j to their tenderfcetmses, till they have sufficient strengti jt and firmness to bear the injuries of the atmospheri i>. and contact of other more solid substances, their bone i are frequently incomplete, and always of a make ii some parts of the body different from those of the r« bust male; which agree with the description alreadl given, unless where the proper specialities of the fe male were particularly remarked; which could not bi i done in all places where they occur, without perpleSi ; ing the order of this treatise: Therefore I chose rathfll ;■ to sum them up here by way of appendix. The causes of the following specialities of the femall .■ bones, inay be reduced to these three ; 1. A weak, la:, constitution. 2. A sedentary inactive life, increasina. that constitution. 3. A proper frame for being mother* The bones of women are smaller in proportion f| their length than those of men ; because the force oil their muscles is not so great, nor is such strong exte»a> nal force applied to them to prevent their stretchinfl,. out in length. The depressions, ridges, scabrous surfaces, and other inequalities made by the muscles, are not so conspicuous in them ; because their muscles are nei- ther so thick nor strong, nor so much employed, as to make so strong prints on their bones. Their osfrontis is more frequently divided by a con- tinuation of the sagittal suture, which depends on the OF THE NERVES IN GENERAL. 227 This fibrous texture is evident at the origin of most ' the nerves within thes kull; and in the cauda equina F the spinal marrow, we can divide them into such nail threads, that a very good eye can scarcely per- iive them; but these threads, when looked at with a icroscope, appear each to be composed of a great amber of smaller threads. 10. How small one of these fibrils of the nerves is, i e know not; but when we consider that every, even tremeTheir le most minute, part of the body is sensible, and thatnuity. iis must depend on the nerves (which, all conjoined, ould not make a cord of an inch diameter) being di- [ded into branches or filaments to be dispersed rough all these minute parts, we must be convinced, it the nervous fibrils are very small. From the ex- lination of the minimum visible, it is demonstrated, it each fibre in the retina of the eye, or expanded die nerve, cannot exceed the size of the 32,400 part ’ a hair. 11. The medullary substance, of which the nervous Coats, irils are composed, is very tender, and would not be lie to resist such forces as the nerves are exposed to ithin the bones, nor even the common force of the 'culating fluids, were not the pia mater and tunica \achnoides continued upon them ; the former giving |em firmness and strength, and the latter furnishing pellular coat to connect the threads of the nerves, to them lie soft and moist, and to support the vessels lich go with them (a). It is this cellular substance that is distended when is forced through a blow pipe thrust into a nerve, 1 that makes a nerve appear all spongy, after being itended with air till it dries; the proper nervous :ils shrivelling so in drying, that they can scarcely observed. 12. These coats, ($ 11.) would not make the nerves ong enough to bear the stretching and pressure they * exposed to in their course to the different parts of body : and therefore, where the nerves go out at OP THE NERVES IN GENERAL. the holes in the craniuvi and spine, the dura mater it fenerally wrapt closely round them, to collect theii x isgregated fibres into tight firm cords; and that th« t tension which they may happen to be exposed to, maj 5 not injure them before they have got this additiona' j coat, it is firmly fixed to the sides of the holes in th« J bones through which they pass (a). 13. The nervous cords thus composed of nervou; | vascular.tremely fibrils, cellular coat, pia and dura mater, have surf arenumerous injected, blood-vessels, the whole cord that is aftertinged their of thearteries colour onlj the injected liquor; and if the injection is pushed vio- lently,sten ethe cellular substance of the nerves is at last Inelast 1Cc ' ^ 14. ^A dnervous with it. cord, such as has been just now de- scribed (§ 13.), has very little elasticity, compared with several other parts of the body. When cut out oi the body, it does not become observably shorter, whil| the blood-vessels contract three-eighths of their length 15. Nerves are generally lodged in a cellular oj fatty substance, and have their course in the inter- stices of muscles, and other active organs, where they are guarded from pressure; but in several parts they are so placed, as if it were intended that they should there suffer the vibrating force of arteries, or the pres- 1 Ca sure of the contracting fibres of muscles. -tiov* ” branchesThe as largerthey gocords off toof thethe differentnerves divideparts; intothe branches being smaller than the trunk from which they come, and making generally an acute angle where they separate. one17- cord, In whichseveral is places,commonly different larger nerves than anyunite of intothe nerves which form it. Ganglions. 18. Several nerves, particularly those which are dis tributed to the bowels, after such union, (§ 17.) sud- denly form a hard knot considerably larger than all densed(a) Zinncellular considers substance, the outerand not coats productions of the nerves of asthe merely dura con-1nia-p log.ter. tom.Monro’s iv. p. Nerv.106. Syst.k. p. 48. and Ludwig, Scriptor. NeurQ-iai THE ANATOMY THE HUMAN NERVES. OF THE NERVES TN GENERAL. 1. The numerous turns which the carotid and verte- Motion of bral arteries make before they pass through the dura the blood 1 mater, these arteries having neither swelling muscles hwithinead> the jl nor pressure of the atmosphere to assist the course of I the blood in them, after they enter the skull, and their f division into innumerable communicating branches in | the pia mater, and its processes, shew, that the liquors i must move more slowly and equally in them than in 1 most other parts of the body. 2. By the assistance of injections and microscopes, Cortical ) the very minute branches of these vessels (§ 1.) are Part of tbe I, liscovered to go from the pia mater into the cortex, encephalon cineritious, or ashy-coloured part of the cereirtm, va8‘ » cerebellum, and spinal marrow ; whereas we can see j mly longitudinal vessels, without numerous ramifica- tions, or reticular plexuses, in the white medullary substance of these parts. 3. The continuity of the cortex with the medulla of the encephalon and spinal marrow, is observable with \e naked eye, and is more distinctly seen with the sistance of a microscope. 4. In dissecting the brain and cerebellum, we see the sail beginnings of the medulla proceeding from the )rtex, and can trace its gradual increase by the addi- ion of more such white substance coming from the cortex. OP THE NERVES IN GENERAL. 5. Both these substances ($ 4.) are very succulent for being exposed to the air to dry, they lose more a their weight than most other parts of the body. * Cerebral 6. In several places, we can observe the medulla t» medulla be composed of fibres laid at each other’s sides. fibrous. 7. The medullary substance is employed in form. ' ingthe white fibrous cords, which have now the nanu " of nerves appropriated to them. Within the skull wt: see the nerves to be the medullary substance coq p tinned; and the spinal marrow is all employed i 5 forming nerves. Origin of 8. The common opinion concerning the rise of th the nerves nerves, founded on a superficial inspection of thoa r uncertain. parts, is, that the nerves are propagated from that sicf ^ of the encephalon, at which they go out of the skull ' But it having been remarked, after a more strict irij * quiry, and preparing the parts by maceration h water, that the medullary fibres decussate or crosj: each other in some parts of the medulla ; as, for eXj ample, at the corpus annulare *, and beginning of thi spinal marrow : And practical observators having re' lated several examples of people whose brain was hurl • on one side, while the morbid symptom, palsy, ap- peared on the other side of the body, of which I have seen some instances ; and experiments made on brutes having confirmed these observations, it has been thought, that the nerves had their rise from that side : of the encephalon, which is opposite to their egreaf from the skull. It may, however, still be said, thatr1: this last opinion is not fully demonstrated, because* f decussation in some parts is not a proof that it obtaiji 1 universally; and if there be examples of palsy of the side opposite to where the lesion of the brain wasi there are also others, where the mjury done to thei brain and the palsy were both on the same side. I ^ Fibrous 9. The nerves are composed of a great many threads! - texture of lying parallel to each other, or nearly so, at their exitl the Nerves. from the medulla (a). * Tuber annulare. E. spiral(a) lines.Monro See2 j, 232 OP THE NERVES IN GENERAL. head, and the influence of the spinal marrow on it ' nerves depends in a great measure on this medulla ol longata of the head. Hence an injury done to an part of the spinal marrow, immediately affects all th ‘ parts whose nerves have their origin below where th ‘ injuring cause is applied. A luxation of a vertebra ii • the loins soon makes the lower extremities paralytic L a transverse section of the medulla at the first vertebr , of the neck, soon .puts an end to life. exceptions.Supposed ( §29. 26, If27, such 28.) causesin us produceand other constantly creatures such living effeci i nearly the same circumstances as we do, the concli) 1 sions already made must be good, notwithstandirij 5u examples of children and other creatures being bor, without brains or spinal marrow ; or notwithstanding 's that the brains of adult creatures can be much changjj ed in their texture by diseases; and that tortoises, am * some other animals, continue to move a considerabl time after their heads are cut off. We may be igna ! rant of the particular circumstances requisite or nece$ f' sary to the being or well-being of this or that parti ' cular creature, and we may be unable to account foi a great many phenomena; but we must believe oui eyes in the examination of facts ; and if we see com stantly such consequences from such actions, we can. not but conclude the one to be the cause and the othei J the effect. It would be as unjust to deny the conclusion! 1 made in the three preceding articles, because of the seemingly preternatural phenomena mentioned at the ! beginning of this, as it would be to deny the necessitj of the circulation of the blood in us and most quadru- peds, because a frog can jump about, or a tortoise can walk long after all the bowels of its thorax and abdo- men are taken out, or because the different parts of ifr■ worm crawl after it has been cut into a great manjw pieces (a). It is therefore almost universally allowedlf or the other of these masses, is denied by some modern writajBb especiallysystems, thoughBichat communicatingand Spurzheim, withwho eachconsider other. them E. as distinct* more(a) generalPerhaps irritability these phenomena or greater are diffusion rather to of be the attributed vital principle to the i, OF THE NERVES IN GENERAL. 229 ie nerves of which it is made. These knots were filled corpora olivaria, and are now generally named tpwgfo’ons. I 19. The ganglions have thicker coats, more nume- -i us and larger blood-vessels than the nerves; so that i ey appear more red and muscular. On dissecting e ganglions, fibres are seen running longitudinally their axis, and other fibres are derived from their ies in an oblique direction to the longitudinal ones. 1 20. Commonly numerous small nerves, which con- nctly are not equal to the size of the ganglion, are at out from it, but with a structure no way different im that of other nerves, (a) 1 21. The nerves sent to the organs of the senses. Pulpy'coh- ie there their firm coats, and terminate in a pulpy sistencct enre offi f bstance. The optic nerves are expanded into the soft D^.n ^s- ' " - 'der webs, the retince. The auditory nerve has .rcely the consistence of mucus in the vestibulum, hlea, and semicircular canals of each ear. The pa- ■ Ice of the nose, tongue, and skin, are very soft. ; JI 22. The nerves of muscles can likewise be traced i i they seem to lose their coats by becoming very ; t; from which, and what we observed of the sensa- :HI: y nerves ($ 21.) there is reason to conclude, that the ( 1 iscular nerves are also pulpy at their terminations, j ich we cajinot indeed prosecute by dissection. 23. It would seem necessary that the extremities of 1 nerves should continue in this soft flexible state, l 21, 22.) in order to perform their functions right: : 1 r, in proportion as parts become rigid and firm by 'I i, or any other cause, they lose part of their sensi- • j1 ty, and the motions are performed with more diffi- !| ty-!4. Though the fibres in a nervous cord are firmly js; ft. H nected, and frequently different nerves join into brilservous not 1 trunk, or into the same ganglion, yet the sensation confounded ach part of the body is so very distinct, and we a e so much the power of moving the muscles sepa- ) e) On the structure of the ganglions, See Monro, Nerv. Syst. IIi> J.in Bichat,Ludwig. Anat. Script. Gener. Neurol, Fart vol. I. anili. p. Haase61. E.De Gangl. Ner- 230 OF THE NERVES IN GENERAL. rately, that, if the nerves be principal agents in these; two functions, which I shall endeavour to prove thej are, we have reason to believe that there is no unioni confusion, or immediate communication of the propel nervous fibrils, but that each fibre remains distinct j, from its origin to its termination. Morbid 25. Changes produced any way upon the coats o| J changes. the nerves, cannot however but affect the nervous n ^ brils. The cellular substance may be too full of liquon | or may not supply enough ; the liquor may not be oi t a due consistence, or it may be preternaturally ob- : structed and collected. The pia or dura mater mad be too tense or too lax; their vessels may be obstruct ed; their proper nerves may be violently irritated, oj lose their power of acting; and a great many othdj such changes may happen, which will not only occal , sion disorders in particular nerves, but may be a causftg of the sympathy so frequently observed among tlfl nerves; which is so necessary to be attentively M garded in a great many diseases, in order to disced™ their true state and nature, that, without this know ledge, very dangerous mistakes in the practice of phyi 'sic and surgery may be committed. Nerves the 26. Many experiments and observations concur jfl instruments proving, that when nerves are compressed, cut, or anyl of sensation, other way destroyed, the parts served by such nervlB and perhaps farther from the head or spine than where the injuringjl of motion. cause has been applied, have their sensations, motio^T and nourishment weakened or lost, while no such a fects are seen in the parts nearer to the origin of tlna nerves ; and in such experiments where the cause nL, peding the nerves to exert themselves could be re- moved, and the structure of the nerves not injure® j;. as, for example, when a ligature made upon a nerved and stopping its influence, has been taken away, the: s(;; motion and sensation of the parts were soon restored*!, From which it would appear, that the nerves are prin- , cipal instruments in our sensations, motions, and nou« . rishment (a); and that this influence of the nerves i (a) It seems now fully proved that the nerves are not imme* j p.diately 78. E.concerned in nutrition. See Monro’s Nenr. Sysb t OP THE NERVES IN GENERAL. 235 t 34. As a further objection against either motion or msation being owing to the elasticity of the nerves, is said, that if this doctrine were true, the sensations k ould be more acute, and the contractions of muscles il ould be greater and stronger, when the parts become ) 'mer and more rigid by age; for then their elastici- ; is increased: Whereas, on the contrary, it appears [ 23.) that then the sensations are blunted, and mus- i.i dar contraction becomes less and weaker, t 35. If the nerves were granted to be elastic, and to a mmunicate a springy force to all the parts to which i 1 ey are distributed, they might appear necessary in is view to assist the application of the nutritious 1 rticles of the fluids to the sides of the vessels which s; ese particles were to repair; and so far might well Hough account for the share which nerves are thought have in nutrition: But if we cannot make use of ii.sticity in the other two functions, sensation and . J rtion, we must also endeavour to find out some other f iy for the nerves to act in nutrition; which will be )pe afterwards (a). .1 36. Having thus stated the reasons for and against Hypothesis ut 3 nerves acting as solid strings, let us likewise relate vousof a ner.uid j 3 arguments for nerves being pipes, and the obiec- f' t ns to this doctrine. examined. | A great argument of those who think the nerves to ill tubes conveying liquors, is the strong analogy of ‘..4 s brain and nerves to other glands of the body and )1 dr excretories, where a manifest secretion of liquor idi made in the glands, to be conveyed by the excre- 4 ies to the proper places in which it ought to be de* if ited. They think that the vascular texture of the i tex of the encephalon and spinal marrow ($ 2.), the it itinuation of the cortex in forming the medullary uair (stance (§ 3, 4.), the fibrous texture (§ 6.), and * culent state of this medulla (§ 5.), and its being oily employed to form the nerves ($7 ) where the •ous texture is evident () 9.): all these things, say conspire to shew such a strong analogy between Ji) On this subject, see Ludwig, Script. Neurolog. T. II. p. 1.Inas, III. Princ. 211. andde Physiolog.IV. p. 195. Tom. Haller, II. Elem.p. 380. Physiol, E. lib. x. xi. ii 236 OF THE NERVES IN GENERAL. these parts, and the other glands of the body, as car- 1 ries a conviction that there is a liquor secreted in thal encephalon ind spinal marroiv, to be sent out by thej nerves to the different parts of the body. ,|r Objections. 37- The following objections are raised to this ar* gument in favour of liquor conveyed in the nerves® from the analogy of the glands. 1. Other glands, ». is said, have their excretories collected into a few largej, pipes, and not continued in such a great mumber oS separate pipes, as far as the places where the liquor* . are deposited; which last must be the case, if the nerves are the excretories of the glandular brain. 2: theWe excretoriessee the cavities, of other and glands can examinemuch smaller the liquors than the i|l : brain; which cannot be done in the nerves. 3- li the nerves were pipes, they would be so small, that the attraction of the liquors to their sides, would pro: vent that celerity in the motion of the liquors, whicl . is requisite to sensations and motions. 4. If the nervefj were pipes, they would be cylindrical, and consequilen* i ly not subject to diseases; or at least we could hav* no comprehension of the diseases in them. Answered. That38. there The areanswer other to glands the first where of thesethere objectionsis a manifeB )| secretion, and in which the disposition of the excr® tories is in much the same way as in the encephaloth The kidneys, for example, have a reticulated corlti of vessels, from which the Eustachian or Belinian me dulla, consisting of longitudinal fibres, and a few blood vessels in the same direction, proceeds; and this mt dulla is collected into ten, twelve, or more pupil each of which is formed of numerous small sepal pipes, which singly discharge the urine into the larg(! membranous tubes ; and these united form the Upon comparing this texture of the kidneys with of the encephalon ; (§ 2, 3, 4, 5, 6, 7> 9.) the am1 will be found very strong. 39. In answer to the 2d objection, in § 37, it granted, that microscopes, injections, and all the otAj arts hitherto employed, have not shewn the cavil! of the nervous fibrils, or the liquors contained in them and from what was said (§ 10.) of the smallness! the nervous fibrils, it is not to be expected that the) I OF THE NERVES IN GENERAL. 233 r iat the nerves are principal instruments in our sen- n ions, motion, and nourishment; and that the in- it ence which they have is communicated from their ni gin, the encephalon and medulla spinalis. But au- ; )rs are far from agreeing about the manner in which s influence is communicated, or in what way nerves ; to produce these effects. , 30. Some allege, that the nervous fibres are all so- Cause of ci cords acting bp elasticity or vibration ; others main- nervous n, that those fibres are small pipes conveying liquors, enerB7- ai means of which their effects are produced. . 31. The gentlemen, who think the nervous fibres Vibration , id, raise several objections to the other doctrine; considered, ri'ich I shall consider afterwards; and endeavour to t • w the fitness of their own doctrine to account for ffe effects commonly observed to be produced by the st ves. 3; The objects of the senses plainly (say they) make 4 raises on the nerves of the proper organs, which it st shake the nervous fibrils ; and this vibration must mpropagated along the whole cord to its other extre- i ;y or origin, as happens in other tense strings; and 't se vibrations being differently modified, according t the difference of the object, and its different appli- .* ion, produce the different ideas we have of objects. . 12. To this account of sensation, it is objected,Objections. ; at nerves are unfit for vibrations, because their ex- 4 mities, where objects are applied to them, are quite I and pappy ($ 21.), and therefore not susceptible he vibrations supposed ; and if there could be any Me tremor made here bv the impulse of objects, it ild no be continued along the nervous cord, be- ta se the cellular substance by which each particular H e is connected to the neighbouring ones ($ 11.) the fatty substance in which the nervous cord is :m nersed (§ 15.) would soon stifle any such vibratory ■ at don. i second objection to this doctrine is, That suppos- )4 the nerves capable of vibrations by the impres- ; 4 ich animals. They seem not to depend on nervous energy. ■ i the oftreatise the Kncylopaedia on Physiology liritannica, drawn No. up 55. by meE. for the 4th 234 OF THE NERVES IN GENERAL. sions of objects, these vibrations would not answe the design. For if what we know of other vibratii strings, to wit, that their tone remains the same, u less their texture, length, or tension be altered, ai that different substances striking them do no moi than make the sound higher or lower ; if these prj perties are to be applied to nerves, then it will follow that the same nerve would constantly convey tb same idea, with no other variety than of its beid weaker and stronger, whatever different objects we! applied to it; unless we supposed the nerve change in its texture, length, or tension, each time a diffe ent object is applied ; which, it is presumed, nobo< will undertake to prove, does happen. Nay, 3t%, If ever such a variety of vibratiol it eould be made, our sensations would notwithstandii I be confused and indistinct, because the tremulous n< vous fibre being firmly connected and contiguous several other fibres of the same cord, would necess rily shake them too, by which we should have t] notion of the object as applied at all the different par* is; where the extremities of these fibres terminate. | 33. In whatever way the favourers of the doctrifl of solid nerves please to apply the elasticity of nerWf : to the contraction of muscles, their adversaries insis ■ that nerves are too weak to resist such weights as muscles sustain; they would surely break, especis as they are in a great measure, if not wholly, depi ed of their strong coats before they come to the parti the muscle on which they are immediately to a (§ 22).—The nerves being found to have little or aj elasticity to shorten themselves ( $ 14.) shews tl altogether unfit for such an office as this of contrs. ing muscles in the way proposed of their acting ® elasticity ; and when a nerve is viewed with a midg scope while the muscles it serves are in action/I contraction or motion is observed in it.—Nay, if tM were elastic, they would equally exert their power, contracting muscles nearer to their origin as well farther from it, when they were put into contract! or vibration, by irritation of any part of them. TI former however does not happen. OF THE NERVES IN GENERAL. &c. by which, in their opinion, the effects com- >nly ascribed to nerves are produced. 43. Besides the objections already mentioned (§ 32, 1.) against the nerves acting as elastic strings, this union has some other difficulties which may be ob- cted to it: For instance, there is not one analogous :ample in the whole body of liquors secreted in a rge gland, to be poured into a cellular substance, as here supposed ; the liquors in the cells of the tela Uularis of other parts are separated from the little teries which are distributed to these cells. Further, it cannot be imagined, how a liquor, se- [eted in the cortex of the brain, should make its way trough the medulla, to come out into the cellular icmbranes on the surface of that medulla. Lastly, A very simple experiment of injecting wa- sr by the artery of any member, and thereby filling e cellular substance of the nerves of that member, lews evidently, that the liquor of the cellular sub- fance of the nerves has the same fountain as the li- lor has in the tela cellularis any where else, that is, jm the little arteries dispersed upon it. 44. The doctrine of a fluid in the nerves, is not only j£ p j_ us supported by the analogy of the brain and nerves mentX er in f the other glands, and their excretories, but those vour of a a io maintain this doctrine, mention an experiment fnervousluid- dch they think directly proves a fluid in the nerves. is this : After opening the thorax of a living dog, tch hold of and press one or both of the phrenic nerves th the fingers, the diaphragm immediately ceases to utract; cease to compress the nerves, and the mus- j acts again: A second time, lay hold of the nerve nerves some way above the diaphragm, its motion jps. Keep firm hold of the nerve, and, with the igers of the other hand strip it down from the fingers nch ake the compression towards the diaphragm, d it again contracts: A repetition of this part of the periment three or four times, is always attended th the same effects ; but it then contracts no more, •ip as you will, unless you remove the pressure, to ie hold of the nerves above the place first pinched ; ten the muscle may again be made to contract, by 238 OF THE NERVES IN GENERAL. 40. The 3rZ Objection to the doctrine of the brai: I being a gland, and the nerves its excretories, suppos es a more rapid motion necessary in the fluid of th nerves, than what most of the defenders of the net vous fluid will now allow; and is afterwards to b: considered particularly in a more proper place. « 41. The Ath Objection being. That if nerves ar excretories of a gland, they must be cylindrical pipejl in which no obstructions or diseases would happer but since we daily see diseases in the nerves, thj it must therefore not be such excretories. The answe is. That diseases happen often in the excretories J other glands, as of the liver, kidneys, &c. notwith: standing their cylindrical form, and their much short ;j er and less exposed course. When we consider tin very tender substance of the brain, the vast complic# »; tion of vessels there, the prodigious smallness of th : pipes going out from it, the many moving powe® h which the nerves are to undergo the shock of, and th many chances which the vessels, membranes, and cel: lular substance accompanying the nerves have of beittt- disordered, and then affecting-the nervous fibrils, w| have very great reason to be surprised, that these cji lindricalof order, bypipes too greatare not or muchtoo small more a quantityfrequently of liquoMi^put by too viscid or too thin fluids; by liquors consisti|jl: of too mild and sluggish particles, or of too acrid pQH>' gent ones; by too great or too little motion given ijl; the liquors; by the diameters of the pipes being He much straitened, or too much enlarged; and byjj: great many other varieties of circumstances whicj ofmight the nerves,be thought supposing capable them of disturbing to be cylindrical the functiflnj excrej tories of the gland, the brain: Fluid se- 42. The numerous vessels of the encephalon hlvi creted by brought some of the gentlemen who assert the nerve , the ence- to be solid, to acknowledge, that there is a liquor se phalon not creted in the brain : But then they will not allow tba poured out this liquor is sent out by the proper nervous fibrils cellularinto the but that it is poured into the cellular substancei . substance. which the nerves lie, to keep them moist and supple f and therefore fit for exerting their elasticity, vibra OF THE NERVES IN GENERAL. 241 icse cases the ceasing of the contraction of the mus- es seems to depend on very different causes, to wit, deprivation of necessary liquors in the one, and a idundancy of superfluous blood in the other. An ! istic stick may be deprived of its elasticity by being j ide45. eitherSome toogentlemen, dry or too convinced wet. of the reasonable- Two kinds ss of the secretion of a liquor in the brain to be sent of nerves t by the nerves, but not comprehending how a fluid supposed ild have such a rapid retrograde motion as they ima- ^ some- led was necessary for conveying the impressions of iects made on the extremities of nerves to the senso- ’,m, supposed two sorts of nerves ; one that convey- a liquor for muscular motion and nutrition; the er composed of solid nerves, that were to serve for n ;ans of the senses, to convey the vibrations com- >L inicated from objects to the sensorium. 116. To this opinion {§ 45.) the objections against Objections. 4 : sensatory nerves acting by vibration ($ 32.) may ri made ; and there is so little reason to suspect any i erence in the texture of the different parts of the i in or nerves, that, on the contrary, the structure is '« ry where similar, and branches of the same nerve ^ ;n serve both for sensation and motion. !Iow little necessity there is for supposing extreme- apid motions of the nervous fluid, is to be exa- ied soon. 7- The hypothesis of great celerity in the motion Division of he fluid of the nerves being necessary, gave also the nerves to another division of the nerves, into arteries or intoous anarteri-ve int, and venous or refluent. It was said, that mus- ^ - .r motion and nutrition depended on the arterious es; and that the sensations depended on an ac- r fl *n •ated motion of the nervous fluid towards the e ™nt n, by the impressions which the objects of the es make upon the venous nerves. By this sup- tion the absurdity of rapid fluxes and refluxes in same canal was prevented, and an advantage was ght to be gained by it, of saving too great a waste le fluid of the nerves, which otherwise the ence- on and spinal martow could not supply in sufli- 0 ; quantity to answer all the exigencies of life. 242 OF THE NERVES IN GENERAL. Objections 48. To this opinion (§ 47.) it has been objected considered. 1. That there is no example in the body of a secret© liquor being returned immediately and unmixed t the gland by which it was originally separated fron the mass of blood; which would be the case wer there venous nerves. 2. There is no occasion fo saving the fluid of the nerves in the way proposed j, the organs for secreting that fluid being large enougj [ to supply all that is necessary of it in the comma; " functions of; life. 3. If the fluid of the nerves was ti. be thus kept in a perpetual circulation, it would sooi | become too acrid for continuing with safety in sucl sensible tender vessels as those of which the brain ani nerves are composed. 4. This hypothesis will no B answer the design for which it was proposed; fa „ though the momentary application of an object migh ; cause an acceleration in the fluid of venous nerves, ye if the object were kept applied to the nerves, it wool , stop their fluid, so that it could not go forward to th brain; and, therefore, according to this doctrine, w should be sensible of no objects except those whose ap plication to the organs of the senses was momenta^ , Supposed 49. Let us now suppose it probable, that the eneb nature of phalon and spinal marrow secern a liquor from th the nervous blood which is sent into all the nerves, and that by th fluid. means of this liquor, the nerves perform the office commonly assigned to them; it is next necessary! inquire what kind of liquor this is, and how it inovet' ■ in order to determine how well its nature and motift are fitted for performing what is expected froma ifit. j.'' Not acid or 50. The liquor of the nerves has been fancied p| alkaline. some to be of a very strong acid or alkaline iiatultj But since none of our juices appear to be of this soft and since such liquors irritate and destroy the parti the body to which they are applied, we cannot c(M ceive how the brain can separate, or the nerves coi~ bear any thing of such an acrid nature. This td derness and sensibility of these organs must hintl us absolutely from supposing that the liquor of tM nerves can be acrid or pungent, or of the nature cl spirit of wine, hartshorn, &c. OP THE NERVES IN GENERAL. .51. Some have imagined the liquor of the nerves to Not a very s i capable of vast explosion like gunpowder, or of elastic 4f ilent sudden rarefaction like air, or of strong ebulli- I n like boiling water, or the mixture of acids with if! aline liquors. But as the mass of blood from which s fluid is derived, is not possessed of any such pro- < ties, we cannot suppose the blood to furnish what 9t ias not in itself. Besides, all these operations are •t violent for the brain or nerves to bear; and when e they are begun, they are not so quickly con- * Lied or restrained, as experience teaches us the * ves can be made to cease from acting (a). 2. We are not sufficiently acquainted with the perries of an cether or electrical effluvia pervading c ry thing, to apply them justly in the animal eco- T ly; and it is as difficult to conceive how they k ild be retained or conducted in a long nervous Ci 1. These are difficulties not to be surmounted (6). 9113- of Thethe nervessurest waymust of be, judging is to examine what kind the liquorsof liquor of Comparedwith other Cl Liar parts of the body. All the glands separate li- secreted j -s from the blood much thinner than the compound ; Ji 5 itself; such is the liquor poured into the cavity : it ic abdomen, thorax, ventricles of the brain, the sali- i * pancreatic juice, lymph, &c. Wherever there is « sion for secreted liquors being thick and viscid, in r to answer better the uses they are intended for, H re has provided reservoirs for them to stagnate in, : s', re their thinner parts may be carried off by the w erous absorbent veins dispersed on the sides of t cavities; or they may exhale where they are ex- to the open air. The mucus of the nose becomes by stagnation; for when it is immediately se- ir||d, it is thin and watery; as appears from the ap- 'tion of the sternutatories, &c. The cerumen of the is of a watery consistence, when just squeezing For arguments in favour of the elastic nature of the ner- 9< iuid,See Monro,see Parr’s Nerv. New Syst. Medic. p. 74. Diction, The identityvol. i. p. of398. the ner-E. ntUuluid d by with the chemicalthe electric philosophers or galvanic of thepower, present has day.been Journ. lately ‘"I ys, Germinal, an. xi. E.M 2 244 OF THE NERVES IN GENERAL. out. The mucus of the alimentary canal grows thfl in the lacunae- The bile in the hepatic duct has litl more consistence than lymph ; that in the gall-bla der is viscid and strong, 'i he urine is much more w tery as it flows from the kidneys, than when it is ei creted from the bladder. The semen is thin as it com from the testicles, and is concocted in the vesiculce minales, &c. An ex- 54. Hence {§ 53.) we may safely conclude, tha tremely thin liquor is secreted in the cortex encephali and ,9 thin liquor.' nal marrow; and seeing the thinness of secreted quors is generally, as the divisions of the vessels, small subtile branches, and that the ramificatio within the skull are almost infinitely subtile, the iff quor secreted in the encaphalon may be determinedff be among the finest or thinnest fluids. 55. Seeing also that we can observe no large res®!1 voir, where the liquor secerned in the corticalsubsiam". is deposited, to have its finer parts taken off, we hai reason to think, that it goes forward into the nerv ‘ in the same condition in which it is secerned. j l 56. By fine or subtile animal liquors, is meant jj ! more than those which are very fluid, and which see to consist of a large proportion of watery particU J and a lesser one of the oily, saline, and earthy par cles. Some of the liquors, which we can have in su ficient quantity to make experiments with, are,* f fluid, and have so little viscidity or cohesion of par) j that when laid upon a piece of clean mirror, they e« porate without leaving a stain ; such is the liqi oozing out from the surface of the pleura, the lym ." and several others. If then these liquors, which are subject to o:, examination, the secerning vessels of which act large that we can see them, have such a small Oi sion of parts, it might not be unreasonable to.i that the liquor of the nerves is as much more fine fluid than lymph, as the vessels separating it smaller; and therefore that the fluid of the nervl a defecated water, with a very small proportion off other principles extremely subtilized. answered.Objections 57- Two experiments are said to contradict It OP THE NERVES IN GENERAL. 245 inion of the liquor of the nerves being so fluid and ibtile. One is, that upon cutting the cauda equina i aegg living drops animal, out: Thea liquor other as is, viscidthat a aswounded the white nerve of ields a glairy sanies. But these do not appear to he le proper fluid of the nerves; since it is evident, 'lat the what cellular is discharged substance in involving both these the cases, nervous comes fibrils. out 58. Considering how many experiments make it ddent, that there is a constant uninterrupted stream “ liquors flowing through all the canals of animals, hich convey liquors composed of particles smaller lan the diameter of their canal, which is always the ise of the nerves in a natural state; it is surprising it ever could be thought that the liquid of the es should be obliged to flow from the brain to ich muscle the moment we will; or that this liquor muld flow back with the like swiftness from the ex- unity of each nerve, to which an object of sensation applied. The nerves, as well as the other excre- •ies of the glands, are always full of liquor; the de- se of distention of the canals not being at all times ike even in a sound state. But this happens without [convenience, as the sides of the canals have a power accommodating themselves to the present quantity, dess it is very much above or below the natural mdard; in both which cases diseases ensue. 59. The motion of the fluid in the nerves is there- Flows with Ire not only constant, but it is also equal, or nearly aan(1 constante< ual : For, though the blood in the larger arteries is ni0tl0n, l ] oved unequally by the unequal forces, the contrac- * >n of the ventricle of the heart, and the weaker si >wer, the slystole of the arteries; yet the difference w tween these two moving powers comes to be less id less perceptible, as the arteries divide into smaller il anches ; because of the numerous resistances which 1 e liquors meet with, and because the canals they V ave in become larger, till in the very small arterious )j anches, there is no sensible difference in the velocity d the liquors from the effect of the heart or arteries, i he motion of the fluids must still be more equal in e excretories of glands, and particularly in those m 3 246 OF THE NERVES IN GENERAL. where the vessels have divided into very minu branches, and the liquors have no other propellij force, but the heart and arteries, (see § 1.); therefo! the nervous fluid moves constantly, equally, and slov ly, unless when its course is altered by the influent of the mind, or by the pressure of some neighbourii; . active organ. 60. As there is neither proof nor probability of tl I valves supposed by some in nerves, we are not to ai ' sume them in accounting for any phenomena. theAction Nerves, of idea61. of We the mannerhave not, in whichand perhaps mind andcannot body have act upaan i(j each other; but if we allow that the one is aflecte by the other, which none deny, and that the fluid < L- the nerves (whatever name people please to give (' is a principal instrument which the mind makes us ( of to influence the actions of the body, or to infori n itself of the impressions made on the body, we mus it allow that the mind can direct this instrument diffef >■ ently, particularly as to quantity and celerity, thong n we must remain ignorant of the manner how many pke, nomena depending on this connection of mind and b« 5 dy are produced. Thus we would in vain attempt ft . account for animals continuing, after their heads wer -. struck off or their hearts were cut out, to perform ac: r tions begun before they suffered any injury. 62. Let us now suppose the nervous fluid such *| . has been argued for, to wit, a very fluid saponaceoui i, water, moving in a constant, equal, slow stream, froa f the encephalon and spinal marrow, in each of the pr« per nervous fibres, except when the motion is change by some accessory cause, such as the mind, pressujff ^ of other parts, &c. and let us examine how well such! v supposition will agree with the phenomena of the thret ’ great functions, nutrition, sensation, and muscular mo- ; tion, of which the nerves are principal instruments, d (■ 63. In general, we may say, that nerves can carry fluids to the most minute part of the body, to supply what is wasted in any of the solids; that the impres- ,| sion made by the objects of the senses on the very soft pulpy extremities of the nerves of the organs of the senses, must make such a stop in the equal-flowing OF THE NERVES IN GENERAL. 247 rous fluid, as must instantaneously be perceptible t the fountain-head from which the pipes affected :|jrise ; that the constant flow of the liquor of the nerves •Tito the cavities of the muscular Jibrillce, occasions the atural contraction of the muscles, by the as constant isus it makes to increase the transverse and to shorten lie longitudinal diameter of each fibre; and that it only to allow the mind a power of determining a eater quantity of this same fluid with a greater ve- . city into what muscular fibres it pleases, to account jr the voluntary strong action of the muscles, 64. But since such a superficial account would not 2 satisfactory, it will be expected, that the principal menomena of these three functions should be explain- 1 by the means of such a fluid as has been supposed; id that the several objections against this doctrine muld be answered. Let us attempt this; and where we annot extricate ourselves from difficulties which may e thrown in, let us honestly acknowledge ignorance. 65. *. If water, with a very small proportion of Nutrition Is and salts from the earth, proves a fit nourishment ofby means >r vegetables, such a liquor as the fluid of the nerves nerves is been described (§ 56.) may not be unfit for _ considered, firing the waste in animals. re J3. The slow continual motion of this nervous fluid 58, 59.) to the most minute parts of the body () 10.) well enough calculated to supply the particles that e constantly worn off from the solids by the circula- an of the liquors and necessary actions of life. y. The greater proportional size of the encephalon in aung creatures than in adults, seems calculated for leir greater proportional growth : For the younger ae animal is, the larger encephalon and speedier "owth it has. X. A palsy and atrophy of the members generally lompanying each other, show, that nourishment, ■isation, and motion, depend on the same cause. «. It was said ()' 26.) that the nerves were princi- %l instruments in nutrition. It was not affirmed, that ley were the sole instruments ; and therefore an trophy may proceed from the compression or other M 4 248 OP THE NERVES IN GENERAL. lesion of an artery, without being an objection to th Sensation. doctrine66. a. hereAll objectslaid down of (ahsense, when applied to theii * proper organs, act by impulse; and this action is cai pable of being increased by increasing the impellin] ' force. In tangible objects, that is clearly evident* 1 the closer they are pressed, to a certain degree, thi 'k more distinct perception ensues. Odorous particle L need the assistance of air moved rapidly, to affect ou: nose. Sapid substances, that are scarcely sufficient to ‘ give us an idea of their taste by their own weight, aril assisted by the pressure of the tongue upon the palate ‘ The rays of light collected drive light bodies beforl them. Sound communicates a vibration to all bodiel ■ in harmonic proportion with it. 1 The impulse made thus by any of these objects on 4- the soft pulpy nerves (§ 21.) which are full of liquor: presses their sides or extremities, and their liquor is 1 hindered from flowing so freely as it did. The canalj ;‘ being all full (§ 58.) this resistance must instantaneous ly affect the whole column of fluids in the canals that are pressed, and their origins, and have the same effect! as if the impulse had been made upon the origin itself.' !• To illustrate this by a gross comparison: Let any one push water out of a syringe, through a long flexible! pipe fixed to the syringe, and he is sensible of resistfe * ance or a push backwards, the moment any one stops; the orifice of the pipe, or closes the sides of it with his fingers. This impulse made on the nerves, and thutl1 communicated to their origin, varies according to the.'1 strength or weakness, the quickness or slowness, the; continuance or speedy removal, the uniformity or ir/l'v regularity, the constancy or alternation, &c. with whidfl objects are applied to the nerves. b. Whenever any object is regularly applied with f due force to a nerve, rightly disposed to be impressed ! by it, and is communicated, as just now explained, to : the sensorium, it gives a true and just idea of the oh- * ject to the mind. c. The various kinds of impulses which the differ- i ent classes of objects make, occasion in animals, which • (a) See the note at p. 245—E. Otf THE NERVES IN GENERAL. 249 ight to have accurate perceptions of each object, a lecessity of having the different organs of the senses riously modified, so that the several impulses may regularly applied to the nerves in each organ ; or, in other words, we must have different organs of the ;nses fitted to the different classes of objects. d. As the objects have one common property of ipulse, so all the organs have most of the properties J the organ of touching, in common with the papillce if the skin. In the nose and tongue this is evident: i n some operations of the eyes we can also perceive » his; as we may likewise do in some cases where f latter is collected in the internal ear. 4 e. These properties, common to the different objects 1 nd organs, occasion frequently uncommon effects in v he application of an object to an organ proper to It nother object of sensation; for sometimes we have t he same idea as if the object had been applied to its i wn proper organ ;—at other times the object is as it ] rere changed, and we have the idea as if the organ t ad had its own proper object applied to it. Thus, for i sample, light is the proper object to be applied to ic eye to give us any idea of colours; yet, when all ght is excluded from the eyes, an idea of light and dours may be excited in us by coughing, sneezing, ibbing, or striking the eye-ball. A cane vibrating, so hi 5■ nnot to excite sound perceptible to the ear, applied 1 > tthe teeth, raises a strong idea of sound ; as a little ij isect creeping in the meatus auditorius also does.— 9 he fingers applied to two rough surfaces, rubbing on d tch other, are sensible of the sound they make; sur- m ions, of any practice in the cure of fractured bones, 'In. bear witness to the truth of this. The fingers iq pped in acid and several other acrid liquors, have a i a msation very like to tasting. Smelling and tasting, A ery body knows, are subservient and assisting to i -ch other. From such examples we have further 10 oof of one general cause of our sensations, to wit, ipulse from the objects; and of such a similarity id relation in the organs, as might give reason for aagining that any one of them would be capable of K reducing the effect of another, if the impulses of the m 5 250 OF THE NERVES IN GENERAL. different objects could be regularly applied to each— | Hence light and sound may affect insects and othei L animals that have not eyes or ears. [ f. If the impulse of an object be applied with due force, but irregularly, a confused idea of the object is raised. Distant objects are confused to myopes, as very near ones are to presbytce. g. If the application of the impulse be regular, buf [ the force with which it is applied be too weak, oui perception of the object is too faint. One may whis- ' per so low as not to be heard. h. If the application of objects be too violent, ano there is any danger of the tender organs of our senses } being hurt or destroyed, an uneasy sensation we cat pain is raised, whatever be the organ thus injured | The object of feeling affects every organ : Thus pres. . sure, stretching, cutting, pricking, acrid salts, pun- ^ gent oils, great heat, violent cold, &c. occasion pain, . wherever they are applied. Besides, every particulai ' organ can be affected with pain by the too violent ap- j plication of its own proper object. Too much light, . pains the eye ; very loud sound stuns the ear ; very odorous bodies, and too sapid objects hurt the nose and t tongue.—A pretty sure proof this, that the objects of our senses all act, and that the organs are all impress- . ed in nearly the same way. i. Since a middle impulse, neither too small nor tool great, is necessary for a clear perception of objects* 1, we should often be in danger of not distinguishing them, if we were not subjected to another law, to wit, that numerous impulses made at once, or in a quick succession to each other, increase our perceptions of . objects. Thus, such a sound as would not be heard! \ on a mountain-top, will be distinctly heard in a wains-', cotted chamber. We feel much more clearly a tangi- , ble object when our finger is drawn along it, thani when applied with the same force, but by a single;; pressure, upon it We make repeated applications of; ,■ odorous and sapid objects, when we wish to smell or taste accurately. The end of a burning stick appears much more luminous when quickly whirled in a cir- . cle than when at rest. OP THE NERVES IN GENERAL. 251 V k. Whenever the uneasy sensation, pain, is raised >y the too strong application of objects, a sort of ne- tejessity is as it were imposed upon the mind to endea- | rour to get free of the injuring cause, by either with- i: lrawing the grieved part of the body from it, as one Retires his hand when his finger is pricked or burnt; ; »r an endeavour is made to force the injuring cause 1< rom the body, as a tenesmus excites the contraction j vhich pushes a.cr\A fceces out of the rectum. In both -tihese operations, a convulsive contraction is immedi- [ tely made in the injured part, or in the neighbour- n ood of it; and if the irritation be very strong or per- t aanent, the greater part of the nervous system be- ll omes affected in that spasmodic or convulsive way. Is i t this necessity which obliges the mind to exert itself l * i respiration, or in the action of the heart, when the ! angs or heart are gorged with blood ? or the iris to 'i ontract the pupil, when the eye is exposed to strong tl ght ? or sneezing to be performed when the nose is d ckled? &c. Wdl not a stimulus of any nerve more ti eadilyected thanaffect thethose other with nerves which of it the is anybody where ? May con- not « bis sympathy serve as a monitor to the mind rather > » employ the organs furnished with nerves thus con- t ected, to assist in freeing it of any uneasy sensation, s-ban to make use of any other organs? Will not this i some measure account for many salutary operations : erformed in the body before experience has taught aJ s the functions of the organs performing them ? .■hii This nisus of the mind to free the body from what a1 i in danger of being hurtful, may serve to explain the ft henomena of a great many diseases, when we are ac. :i. uainted with the distribution of the particular nerves; | id from this we can understand the operation of me- .ti icines that stimulate; and may learn how, by excit- ig a sharp, but momentary pain, we may free the 71 idy from another pain that would be more durable; 1 id that, by having it thus in our power to determine ’0 flow of the liquor of the nerves to any particular part, ) ir the benefit of that part, or the relief of any other diseased part, we can do considerable service by a i ght application of the proper medicines. 252 OF THE NERVES IN GENERAL* 1. If a pain-giving cause be very violent or long con- tinued, it either destroys the organs irrecoverably, or puts them so much out of order, that they only grai dually recover. People have been blind or deaf forj all their lives after a violent effect of light on their eyes, or of sound on their ears; and we are frequently exposed to so much light and sound as to make us un- fit to see or hear for a considerable time. I would ex-. r; plain this by a ligature put round the tender brand of an herb. This ligature, drawn to a certain degree i, may weaken the canals so as to be unfit for the circu- lation of the juices a good while, till they are gradul 5 ally explicated and made firm by these juices: stricter ligature would disorder the structure of the fi| > bres so much, that the liquors could not recover them! s. The analogy is so plain, that it needs no commentaryl Thus, the influence of a nerve, tied with an artery ins the operation for aneurism, may cease for some timej ?!e Muscular but be afterwards recovered (a). motion. action67. 1.of Inmuscles, applying it wasthe said,fluid thatof the the nervesnatural to or the:'-«,in4 ^ voluntary contraction of the muscles, was the nisnsr^ which the nervous fluid, flowing constantly into the'!, muscular fibres, makes to distend these fibrils, by en-l| . larging their transverse diameters and shortening their*! , axis; and that voluntary contraction was owing to a f greater quantity of that nervous liquor determined to- wards the muscle to be put in action, and poured withj t, greater tnomeniiim into the muscularfibrils, by the poivemL of the mind willing to make such a muscle act, or obligH,. ed to do it by an irritating pain-giving cause (j 66. kM (. Objections. 2. Some object to this account of muscular motionjf ^ that if there be no outlet for the liquor supposed to be poured into muscular fibres, muscles would always be in a state of contraction, which they are not; and if - there be a passage from the fibrils the liquor wouldf. , flow out as fast as it was thrown in; and therefore no distention of the fibres or contraction of the musclesi - could take place. ; siol.(a) T. On II. the Cuvier,Physiology Lee. of d’Anat. Sensation, Comp. see Dumas,T. II. Bichat,Prin. de Anat., Phy- : toGener. the Vit. Disc, Func. prelimin. and Gallois, Wilson, Experiences Philip. Experiment. aar la vie.—E. Inquiry in- ‘: OF THE NERVES IN GENERAL. 253 3. In answer to this objection, it is observed, that Answered, lotwithstanding the evident outlet from the arteries i nto the veins, yet the arteries are distended by the tystole of the heart, or any other cause increasing the Yomentum of the blood. 4. It has been also objected to $ 1. that, if it were •ue, the volume of the muscle in contraction neces- arily would be considerably increased by so much li- uor poured into its fibrils; whereas it does not ap- I >ear, by any experiment, that the volume of a muscle i s increased by its being put in action. < 5. To this it has been answered, 1. That when the |i xis of muscular fibres are shortened, and their trans- t. erse diameters are enlarged, the capacities of their n bres, and consequently their volume, may not be • i! hanged, the diminution one way balancing the in- £ .ease in the other. 2. That the spaces between the ai mscular fibres are sufficient to lodge these fibres when 1 ley swell, during the contraction of a muscle, without Jiy addition to its bulk; and that it plainly appears 3 lat these spaces between the fibrils are thus occupied, J y the compression which the larger vessels of mus- <« es, which run in those spaces, suffer during the ac- i! on of the muscle; it is so great as to drive the blood ij i the veins with a remarkable accelerated velocity. .1 6. Another objection to the action of muscles being , ui (ving to the influx of a fluid into their fibrils, is, That m mscular fibres are distractile, or capable of being A ;retched; and, therefore, when a fluid is poured into iii icir hollow fibrils, they would be stretched longitudi- /[ illy, as well as have their transverse diameters in- gjj ’eased; that is, a muscle would become longer, as well 1 > thicker, when it is put in action ; whereas it is cer- 4 .inly known that a muscle is shortened while acts. J 7- In answer to this, it has been remarked. That ju lough muscular fibrils are distractile, yet they will r it yield to, or be stretched by every force, however .ii nail, that might be applied to them. A cord that in be stretched in length by the weight of a pound or •i ro, would not yield in the least to an ounce or two; i hd it must likewise be observed, that gradually as any Italy is tretched, its resistance to the stretching force 254 OP THE NERVES IN GENERAL. increases. A rope may be stretched to a certain length ■ by a pound weight appended to it, which would re- quire two pounds to stretch it very little further; and therefore the general observation of animal fibres be- 1 ing distractile, cannot be a reasonable objection to the account of muscular motion above mentioned, unless “ proof be brought that the force which the liquid of ! the nerves must exert upon each fibre of a muscle, ;* in order to make it act, is capable of distracting or stretching the fibres ; which has not yet been attempt^ 1,1 ed to be proved. It would appear from the pain caus- ed by too great an effort of muscles, especially in weaki fei people, that muscular fibres can bear very little dis- 1 traction, without danger of a solution of continuity. 8. Muscles ceasing to act when their arteries are;; tied or cut, and being brought into motion by inject- ^ ing liquors into the arteries even of a dead animal,, L: have been mentioned as objections to the nervous in- fluence causing their contractions. To the first of these experiments it may be answered,, That the trying or cutting the nerves, sooner produces ' the effect of making the contraction cease, than stop- ^ ping the influx of the arterious blood does; and it will be universally allowed, that the influxof blood into mus- ' J cles is necessary for performing their functions aright.. Whoever observes the motion, which injecting wa- ter or any other liquor into the arteries of a dead ani- mal causes in its muscles, will not compare it to that ' contraction, whether voluntary or excited by irritalj ^ tion, which he may see in a living one. i 1 9. If muscular motion depends on the influx of the nervous liquid, the instantaneous contraction of a muscle, when the mind wills to make it act, will be easily understood from the nerves being always full of their liquor (§ 58, 66. a.) nish' 10. a Ifsufficient either quantitythe nerves of of their any liquor,muscle ordo if not the fur- fi- * bres of a muscle become too easily distractile, such a muscle will be inactive or paralytic. be 11.determined If too great to aa quantity muscle ofor themuscles, liquor byof theany nerves cause which the mind cannot command, such muscle ot muscles will be convulsed. OF THE NERVES IN GENERAL. 255 I 12. If the motion of the liquid of the nerves be not i'miform, but by disease become irregular, an alternate I 'elaxation and contraction of muscles may be the con- nequence. Hence trembling, palsies, chorea Sancti ' Piti, &c. Hence also the convulsive tremors which li inimals have when they lose much blood. ! 13. Though the nerves may not furnish so much li- r (,uor as may be sufficient to make muscles contract with 5 trength enough to overcome the resistances to their i ctions, yet there may be a sufficient quantity of li- d [uor in the nerves to allow the impressions of objects 1,0 be conveyed to the sensorium. This may be one :: ause of a member’s being sometimes sensible after it ;ri annot be moved. 14. Unless the liquor of the nerves acquire some ; |i henergy circulation in the brain, of the which fluids we in havethe vessels no reason can to give think it, 7 r unless it have other properties than what we can ■ 0 iscover in it, or unless there be an agent regulating i ;s momentum and course to different parts which we re not conscious of; if some of these, I say, do not 7; 3tain, the action of the heart continuing of equal force c] > propel our liquors, notwithstanding all the resist- inces that are opposed to it, is not to be explained. 1 15. All muscles, but especially the heart, continue i > contract in an irregular way, after they are cut i tvay from the animal to which they belonged; which < lay be owing to the liquors continuing to flow in the u nail vessels, and being poured irregularly into the la inscular fibrillce. : 16. It is said that a muscle cut out of the body con- ii nues some time to be capable of contraction; where- ! i, by tying its arteries or nerves, while it is other- a ise entire in the body, it loses its contracting power, / hich therefore does not depend on these organs, the i j-teries or nerves. 31. The loss of the power of acting when the arteries or • i irves are tied, while the muscle is in the body, is de- 0 ed by some who made the trial, and it might be ex- 1 icted that the motion of a muscle would be more i n nspicuous where there is no resistance to it, as is the ; se when it is cut away from all the parts it is con- 256 OF THE PARTICULAR NERVES. nected with, than when its connexion remains witl parts resisting its contractile efforts. from17- anAfter animal, the hasheart, ceased or any to contract,other muscle, its contractioi cut awaj may again be restored, by breathing upon it, or prick' ^ ing it with any sharp instrument. That heat or prick* ing should, by their stimulus, (§ 56. h.) occasion con« ; traction in a living creature, may be understood; bu| how they should have the same effect, in a muscle se* ' parated from an animal, I know not (a). Ganglions. 68. Some have thought the ganglions of nervei ■ (§ 18, 19, 20.) to be glandular, and that they perforn |6 a secretion. Others, from their firm texture, suppos them to be muscular7 and that they serve to accelerat ^ the motion of the liquor in the nerves which procee< 5 from them ; but as no proof is offered of either of thes ! opinions, they cannot be maintained. Others wouli make them serve, 1. To divide a small nerve into man; '! nerves, and by these means to increase the number d nervous branches. 2. To make nerves come convenienfl ly by different directions to the parts to which the# belong. 3. To re-unite several small nervous fibres into one large nerve. Since no proof is brought thatl these three things cannot be done without the inter* i position of a ganglion, but, on the contrary, we see them performed where there are no ganglions, we must continue to acknowledge ignorance concerning the'r uses of these knots, the ganglions (b). OF THE PARTICULAR NERVES. It is generally said, that there are forty pairs (nit nerves in all; of which ten come out from the encJP ' on («)nervous On the power, dependence see Whytt’s or independence Physiolog. Essays; of muscular Monro’s irritabifj Nei CroonianSyst. p. 99; Lectures Dumas, on MuscularPrincipes Motion de Physiol, in the tom.Philos. III. Trans— and t merring,(b) On De the Hast nerves Enceph.; in general, Prochaska, see Monro’s Destruct. Nerv. Nervor. Syst; Scarpa.-. Soe'mj ofAnnotat. Gall and Academ Spurzheim.—E. ; Ludwig, Scriptor. Neurolog. and the Work! OF THE PARTICULAR NERVES. 25? Malon, and the other thirty have their origin from the minal marrow (a). It Of the ten pairs of nerves which come from the ence- Olfactory malon, the first is the Olfactory, which long had the Nerves, i jame of the mammillary processes of the brain, because ! the brutes, cows, and sheep, which were most corn- only dissected by the ancients, the anterior ventricles 1 the brain are extended forwards upon these nerves, id adhere so firmly to them, that they seem to make e upper side of the nerves. Each of them being rge, where it begins to be stretched out, and gradu- ly becoming smaller as it approaches the cribriform me, was imagined to resemble a nipple. Those who istook the ventricles for part of the nerves, observ- g the cavity in them full of liquor, concluded, that i; ese olfactory nerves served to convey the superflu- is moisture of the brain to the holes of the ethmoid ne through which it passed into the nose. But in an, the ventricles of whose brain are not thus extend- : . forwards, these nerves are small, long, and without i y cavity, having their origin from the corpora stria- {i! {b), near the part where the internal carotid arte- s is are about to send off their branches to the diflfer- j t parts of the brain ; and in their course under the i terior lobes of the brain, which have each a depres- i n made for lodging them, the human olfactory nerves ai come larger, till they are extended to the cribriform ,ii ne, where they split into a great number of small ill iments, to pass through the little holes in that bone; .: d, being joined by a branch of the fifth pair of nerves, ji : spread on the membrane of the nose, d The contrivance of defending these long soft nerves i i m being too much depressed by the anterior lobes u the brain, under which they lie, is singular; be- st ise they have not only the prominent orbitar pro- a) It is now, more than ever, an object of dispute, whether :£u erminateit are called in thatthe cerebral mass. nervesModern proceed anatomists from differthe encephalon, much in isil it,number as immediately of primary connected pairs ; some with reckoning the brain.-—E. nine, others only i’ptt jfe) appears The origin not to of be the distinctly olfactory ascertained.—E. nerves is still a disputed point, 358 OF THE PARTICULAR NERVES. cesses of the frontal bone to support the brain on eac'. side, with the veins going into the longitudinal sinut i and other attachments bearing it up, but there is groove formed in each lobe of the brain itself for then “ to lodge in. Their splitting into so many smal 1 branches before they enter the bones of the skull, i ■ likewise peculiar to them ; for generally the nerve k come from the brain in disgregated filaments, are '■« unite into cords, as they are going out at the holes • t the bones. This contrivance is the best for answerinj the purpose they are designed for, of being the oragj membraneof smelling of; thefor nosehad intothey abeen medullary expanded web, upon such tli 9 *ft the optic nerves form, it would have been too sensible t Ha bear the impression of such objects as are applied ts J the nose; and a distribution in the more common wajj «« of a cord sending off branches, would not have been If equal enough for such an organ of sensation (a). OpticNerves. theThe thalami second nervorum pair of opticorum nerves, the(b), Optic,make a risinglarge curvfron ith outwards, and then run obliquely inwards and for i wards, till they unite at the fore-part of the sella turd ca f then soon divide, and each runs obliquely for wards and outwards to go out at its proper hole in thi sphenoid bone, accompanied with the ocular artery ti to be extended to the globe of the eye, within whicl i- each is expanded into a very fine cup-like web, tha it! lines all the inside of the eye as far forwards as th If ciliary circle, and is universally known by the nami of retina. Though the substance of this pair of nerves seem i. to be blended at the place where they are joined; ye 1 observations of people whose optic nerves were no joined, and of others who were blind of one eye froir a fault in the optic nerve, or in those who had one * > their eyes taken out, make it appear that there is no and(а) Monro,See Hunter Nerv. on Syst. some p. parts 146. of Tab. the Animalxxiv. Economy,E. p. 218-' •rise(б) fromGall andthe corporaSpurzheim quadrigemina. deny this, andThat think this that is thesethe casenerr« ir ' notsome proved quadrupeds a similar they origin seem into man.have demonstrated,E. but they havf ininction oftheopticnerveswillnotservetoaccount j^use oftheremarkablesympathyoneeyewith t jyesdifferentways,isalsoaplainproof,thatthecon- Iffected eyetotheoriginofnerveonsame jhe affectedsideonlybeingwasted,whiletheother Tide. Inmanyfishes,indeed,thedoctrineofdecussa- or eithertheuniformmotionsofoureye*,see- Jg objectssinglewithtwoeyes,thoughitmaybeone laving neitherseenobjectsdouble,norturnedtheir ifrts ofbodies,whosepicturefallsonthiscentralpart kbstance ofthisnerve,asiscommontoothernerves, ' inisfavoured;fortheiropticnervesplainlycross I iswithdifficultythatwecanobserveitsnervous le otherinmanydiseases(a). ,1 on, appearsaveryfineweb,withsomeblood-vessels, ach intimateunionofsubstance:theopticnerve edullary substance.Thesituationofthesevessels ly bethereasonwhywedonotseesuchbodies,or is largeandplump.Andthesameobservationsare iderness intheeyes,andinabilitytobearlight, j generallyattended,mayverywellaccountforthe •e itisexpandedatitsentryintotheballofeye, the retina.Aninflammationinthosearteriesof llary fibreshere,andthefirmnessofthisnervebe- The retinaofarecenteye,withoutanyprepara-Retina. e joinedinmenandmostquadrupeds. ch other,withoutanyunionatthepartwherethey the centralpartofopticnerve;wantme- Those peoplewhoseopticnerveswerenotjoined, rves ($8.);forthediseasecouldbetracedfrom atradictory tothedoctrineofadecussationall jr agoodinjectionofthearteriesthatrunin ling fromitscentretobedistributedonit;but, retina, withwhichseveralfeversandanoptkalmia els losetheirtone,andremain preternaturallydia- sts areseenbypeoplein some fevers.Ifthese cially, andforthatsmoky fogthroughwhichall ion ofthesevesselsmaylikewiseservetoaccount :h peoplehaveinthesediseases.Theover-dis- he blackspotsobservedon bright-colouredbodies (a) SeeWellsonsingleVision with twoEyes.E. ill i if OF THEPARTICULARNERVES. OF THE PARTICULAR NERVES. tended, no objects affect our retina though the eye ex- i; ternally appear sound; or this may be one cause of ■ sionan amaurosis of these vessels,or gutta or serena. par ah/sis From of a apart partial of the distem relu !i na, the central part, or the circumference, or any othef i part of objects, may be lost to one or both eyes (a). | ( Third Pair. processusThe Third annularis Pair* riseand from piercing the anterior the dura part mater of th« f t.is little before, and to a side of the ends of the posteriol ft clinoid process of the sphenoid bone, run along the re* it ceptacula, or cavernous sinuses, at the side of the ephifi t pium, to get out at the foramina lacera ; after vvhicl * each of them divides into branches, of which one, aflfi ter forming a little ganglion, is distributed to the globj of the eye the others are sent to the muscular rectus1, s of the pnlpebra, and to the atlollens, adductor, deprl » mens, and obliquus minor || muscles of the eye-ball j* These muscles being principal instruments in the mo- i- tions of the eye-lid and eye-ball, this nerve has thera v fore got the name of the motor oculi. I have frequeni t. ly observed in convulsions the eye-lids widely opene< b the cornea turned upwards and outwards, and the eye* 1 balls sunk in the orbit; which well described the con- junct action of the muscles which this pair of nerv« : serves- The distention of a considerable branch of the carotid, which passes over this nerve near its ori- it gin on each side, may possibly be the reason of the heaviness in the eye-lids and eyes, after drinking hard;: or eating much (/>). FourthPair. of Theany, Fourthderive their Pair, origin which from are the the back-part smallest nerve*of the (а) On the termination of the retina, see Monro on the Brainy Human.—E.the Eye, and the Ear, p. 94 ; and Soemmerring, Icon. OcuU • MotoresTuher annulare.—E. oculi, common Oculo-muscular nerves.—E. ,C • $|| LevatorObliquus palpebraeinferior oculi su peri Alb.—E. oris All). E. Tab.(б) iv.See fig. Zinn, 1.—E. Descript. Anatbm. Ocul. Human, cap. 9. OF THE PARTICULAR NERVES. 261 ie of the testes*; and then making a long course on le side of the annular protuberance, enter the dura \ater a little farther back, and more externally than she third pair, to run also along the receptacula to pass rat at the foramina lacera, and to be entirely spent on he muscnli trochleares, or superior oblique muscles of he eyes. These muscles being employed in perform- ing the rotatory motions, and the advancement of the ^ye-balls forward, by which several of our passions are txpressed, the nerves that serve them have got the lame of Pathetici. Why these small nerves should i brought so far to this muscle, when it could have sen supplied easily by the motor oc.uli, I know not (a). The Fifth Pair f are large nerves, rising from the Fifth Pair, innular process where the medullary processes of the •erebellum join in the formation of that tuber, to enter ;he dura mater near the point of the petrous process of { he temporal bones; and then sinking close by the re- .« eptacula at the sides of the sella turcica, each becomes n appearance thicker, and goes out of the skull in ji hree great branches. 1 i he first branch of the fifth is the Opthalmic, Opthalmie iivhich runs through the foramen lacerum to the orbit, nerve, v laving in its passage thither a connexion with the i: ixth pair. It is afterwards distributed to the ball of s he eye with the third; to the nose along with the ol- 1: actory, which the branch of the fifth that passes « hrough the foramen orbitarium internum joins, as was j Iready mentioned in the description of the first pair. i■ 'his opthalmic branch likewise supplies the parts at } j he internal canthus of the orbit, the glandula lacryma- , fs, fat, membranes, muscles, and teguments of the -i ye-lids ; its longest farthest extended branch passing i oi hrough the foramen superciliare of the os frontis, to h e distributed to the forehead (6). - 1 The small fibres which this first branch of the fifth ii nd the third pair of nerves send to the eye-ball, being ^ * Corpora quadrigemina.— E. (| •j +(a) Trigemini, See Zinn, cap.trifaciales. ix. § 5. Spurzheimtab. vi. fig. traces1.—E. these nerves to ((ju le(A) upper See Zinn,part of tab. the vi.corpora fig. I.—E. olivaria.—E. OP THE PARTICULAR NERVES. situated on the optic nerve, and, after piercing the t sclerotic coat, running along the choroid coat on thelf outside of the retina in their course to the uvea or irit. may be a cause of the sympathy between the optic nerve and the uvea; by which we more readily ac- quire the habit of contracting the iris, and thereby lessen the pupil, when too strong b'ght is excluded; ' and, on the contrary, enlarge the pupil, when the f light is too faint. This, with the sympathy which 1> ■ must arise from some of the nerves of the membrane of the nostrils, being derived from this first branch oi I 1 the fifth pair of nerves, may also be the cause, why i an irritation of the retina, by too strong light, may f* produce sneezing, as if a stimulus had been applied to the membrane of the nose itself j—why pressing the i internal canthus of the orbit, sometimes stops sneezings 9k why irritation of the nose or of the eye causes the eye- > lids to shut convulsively, and makes the tears flow :i plentifully; and why medicines put into the nose of- ten do great service in diseases of the eyes. In the me- ‘ grim all the branches of the nerve discover themselveii to be affected: for the forehead is racked with pain, the eye-ball is pained, and feels as if it were squeezed*1 < the eye-lids shut convulsively, the tears trickle down,, and an uneasy heat is felt in the nose. Hence we cam r understand where external medicines will have the best: 1 effect, when applied to remove this disease, to wit, to' the membrane of the nose, and to the forehead;—why r alternate pressure near the superciliary hole of the!1 frontal bone, or sneezing, sometimes gives immediatij r relief in the megrim ;—why the sight may be lost by ! an injury done to the supra-orbitar branch;—how it; may be restored by agitation of that branch of this i ts nerve. 1 In Superior The second branch of the fifth pair of nerves may * nerve.maxillary beprincipally called Maxillaris the parts of theSuperior, upper jaw. from It itsgoes serving out at f>jt» the round hole of the sphenoid bone, and sends iinme- tea diately one branch into the channel on the top of the «: antrum maxillare; the membrane of which and the f; upper teeth are supplied by it in its passage. As this branch is about to go out at the foramen orbitarium ex- OF THE PARTICULAR NERVES. 'num, it sends a nerve through the substance of the r maxillare to come out at Steno’s duct, to be distri- ted to the fore-part of the palate; and what remains it escaping at the external orbitar hole, divides into great many branches, that supply the cheek, npper- p, and nostril. The next considerable branch of the superior maxillary nerve, after giving branches which •e reflected through the sixth hole of the sphenoid ic, to join the intercostal where it is passing through i skull with the carotid artery, and the portio dura bjf the seventh pair, as it passes through the os petro- is sent into the nose by the hole common to the j klate and sphenoidal bone; and the remaining part if this nerve runs in the palato-maxillary canal, giving T branches to the temples and pterygoid muscles, and ) i»mes at last to the palate to be lost. Hence, tooth- 1 ph in the upper jaw occasions a gnawing pain, deep- 5 »ated in the bones of the face, with swelling in the ! fe-lids, cheek, nose, and upper-lip; and on the other b tnd, an inflammation in these parts, or a megrim, is a ten attended with sharp pain in the teeth. Hence, < obstruction in the duct of the maxillary sinus, h rich obliges the liquor secreted there to find out a ■5 eternatural route for itself, may be occasioned by the I in in the teeth. Hence, the upper lip often suffers m len the palate or nose is ulcerated. 1 The third or Maxillaris Inferior branch of the Inferior I th pair going out at the oval hole of the sphenoid nervemaxillary ,(i ne, serves the muscles of the lower jaw, and the ‘ • iscles situated between the os hyaides and jaw: All jj 9 salivary glands, the amygdalae, and the external . r, have branches from it. It has a large branch lost a the tongue, and sends another through the canal in ■ 5 8 substance of the lower jaw to serve all the teeth j ?re, and to come out at the hole in the fore-part of j, 9 jaw, to be lost in the chin and under-lip (a).— o mce a convulsive contraction of the muscles of the n ver-jaw, or the mouth’s being involuntarily shut, a jat flow of spittle or salivation, a pain in the ear,espe- {lly in deglutition, and a swelling all about the throat, (o) Monro's Nerv. Syst. p. 149. Tab. xxv. E. 264 OF THE PARTICULAR NERVES. are natural consequences of a violent irritation of th nerves of the lower teeth in the tooth-ach ; and pai; in the teeth and ear, is as natural a consequence of ai angina. Hence alternate pressure on the chin ma; sometimes relieve the violence of tooth-ach. Henci destroying the nerves of a tooth by actual or potentia cauteries, or pulling a carious tooth, so often remove immediately all these symptoms. Hence no cure i; to be found for some ulcers in the upper or lower jaw but by drawing a tooth. Hence in cancers of the up , per lip, the salivary glands are in danger of being af , fected, or the disease may be occasioned in the lip bj i its beginning in the glands. Perhaps.the sympathy®! , the organs of tasting and smelling may, in some mea^ sure, depend on their both receiving nerves from tin fifth pair. Sixth Pair. fourth,. The Sixthrises from Pair*, the whichfore-part is theof thesmallest corpora except •pyrami. tltf ’ dalia(a), and each entering the dura mater some warn behind the posterior clinoid process of the sphenom bone, has a long course below that membrane, ancl within the receptaculum at the side of the sella turcicali where it is immersed in the blood of the receptacle V but for what purpose I am ignorant. It goes after! wards out at the Joramen lacerum into the orbit, Mi: serve the abductor muscle of the eye. A defect nf this nerve may therefore be one cause of strabismus In the passage of this nerve below the dura mater,) lies very contiguous to the internal carotid artery, and to the opthalmic branch of the fifth pair of nerves (b)l At the place where the sixth pair is contiguous to thp carotid, a nerve either goes from each of them in an uncommon way, to wit, with the angle beyond where it rises obtuse, to descend with the artery, and to form the beginning of the intercostal nerve, according the common description; or, according to other au- thors, this nerve comes up from the great ganglion of the intercostal, to be joined to the sixth here. * Abductor nerve, external oculo-muscular.—E. (а) From a small band between the corpora pyramidulia olivaria,(б) Zinn, according de Ocul. to human,Spurzheim.—E. cap. 9. § 6.—E. OF THE PARTICULAR NERVES. The arguments for this latter opinion are, That, : iccording to the common doctrine, this beginning of tjhe intercostal nerve, as it is called, would rise in a i lanner not so ordinary in nerves. In the next place, it i observed, that the sixth pair is larger nearer to the (rbit, than it is before it comes to the place where i lis nerve is said to go off; and, therefore, it is more i robable, that it receives an addition there, rather than ives off a branch. Lastly, It is found, that upon cut- | ng the intercostal nerves of living animals, the eyes rrere plainly affected; they loslr their bright water; • le gum, or gore, as we call it, was separated in greater iiantity;s the pupil was more contracted; the carti- i ginous membrane, at the internal canlhus, came more |t rer the eye; and the eye-ball itself was diminished- ? To this it is answered, in defence of the more com- i on doctrine, Irf, That other branches of nerves go off 3-1i ea beginningreflected way, of theas wellintercostal; as this, supposingand that itthe to re-be ji ixion would rather be greater, if it be thought to ; i me up from the intercostal to the sixth—’idly, It is 9 nied that this nerve is in general thicker at its fore i m its back-part; and if it were supposed to be -1 ckest nearer to the orbit, the conclusion made above i ild not be drawn from this appearance, because : 1 icr nerves enlarge sometimes where there is no ad- i* ion made to them, as in the instance already men- b| ned of the trunk of the fifth pair, while below the ,r■ d *a mater.—3dly, The experiments on living animals v. a w indeed, that the eyes are affected upon cutting i' 'ntercostal nerve, but not in the way which might been expected, if the intercostal had furnished a share of the nerve that goes to the abductor cle of the eye ; for it might be thought that this cle would have been so much weakened immedi- r upon cutting the intercostal, that its antagonist, idductor, would have greatly prevailed over it, and i turned the eye strongly in towards the nose; :h is not said to be a consequence of this experi- t. So that the arguments are still equivocal; and s observations and experiments must be made, be- it can be determined with.certainty, whether the 266 OF THE PARTICULAR NERVES. sixth pair gives or receives a branch here,here. In thi I mean time, I shall continue to speak about the origii of the intercostal with the generality of anatomists. Beginning At this place, where the intercostal begins, the fiftl of the in- pair is contiguous and adherent to the sixth; and it i tercostal generally said, that the opthalmic branch of the fiftl gives a branch or two to the beginning of the intei costal, or receives such from it. Others deny an such communication between them; and those wb affirm the communication, confess, that in some sui jects they could not see it. After examining tb nerves here in a great many subjects, I cannot detel mine whether or not there are nervous filaments goit [, from the one to the other. Sometimes I have thougl [ that I traced them evidently; at other times I observe , that what I dissected for nervous filaments, was coi ^ lapsed cellular substance; and in all the subjects whe^ I had pushed an injection successively into the ver r small arteries, I could observe only a plexus of vessei j connecting the one to the other. In any of these way , however, there is as much connexion as, we are a! sured from many experiments and observations a other nerves, is sufficient to make a very great sym . pathy among the nerves here. Possibly the appeai ance in the eyes of dogs, whose intercostal nerves wei cut, might be owing to this sympathy. The Seventh Pair (a) comes out from the later Seventh 1>art of the annular process, behind where the medu ar processes of the cerebellum are joined to that H her ; and each being accompanied with a larger artj than most other nerves, enters the internal meatus am torius, where the two large bundles of fibres, of wlj it appeared to consist within the skull, soon sepa^ from each other; one of them, entering by several si holes into the vestibule, cochlea,and. semicircular ca is stretched on this inner camera of the ear in a generally(a) Some been modern called anatomists branches regardof the the seventh two nerves, pair, whichas distin M nervenerves, from having the angledifferent formed origins. between Spurzheim the pons varoliiderives and the cwjpt fact . retiforme,medullary whilestreaks he on places the surfacethe origin of theof the fourth auditor ventricle—Em OF THE PARTICULAR NERVES. 267 soft pulpy substance; and being never seen in the form of a firm cord, such as the other parcel of this |and most other nerves become, is called Portio Mol- lis * of the auditory nerve (a). The other part of this seventh pair passes through* [Galen’s foramen caecum, or Fallopius’s aquceduct, in its crooked passage by the side of the tympanum; in which iassage, a nerve sent from the lingual branch of the nferior maxillary nerve, along the outside of the tuba Eustachiana, and cross the cavity of the tympanum, vhere it has the name of chorda tympani, is commonly said to be joined to it. The very acute angle which ;his nerve makes with the fifth, or the sudden violent Reflection it would suffer on the supposition of its i :oming from the fifth to the seventh, appears unusual; ; vhereas, if we suppose that it comes from the seventh ;o the fifth, its course would be more in the ordinary : vay, and the chorda tympani would be esteemed a : iranch of the seventh pair going to join the fifth, the 9 ize of which is increased by this acquisition. This iB mailer bundle of the seventh gives branches to the M luscles of the malleus, and to the dura mater, while it t passes through the bony crooked canal, and at last « omes out in a firm chord, named Portio Dura f, at J he end of this canal, between the styloid and mastoid M recesses of the temporal bone, giving immediately ae laments to the little oblique muscles of the head and f ) those that rise from the styloid process. It then fj ierces through the parotid gland, and divides into a Bl reat many branches, which are dispersed in the 4 luscles and teguments that cover all the side of the apper part of the neck, the whole face and cranium, ; s far back as the temples, including a considerable J art of the external ear. Its branches having thus a ,1 msiderable connexion with all the three branches of b le fifth pair, and with the second cervical, occasion a ic msiderable sympathy of these nerves with it. Hence, oi i the toothach, the pain is sometimes very little in the I(: *(a) Acoustic See an admirableox- auditory representation nerve.—E. of the distribution of the I‘(|i rtio-|- Facialis, mollis, in sympatheticus Scarpa, De Auditu minor.—E. et Olfactu—E. OF THE PARTICULAR NERVES. affected tooth, compared to what it is all along the side of the head and in the ear. Hence probably the relief of tooth-ach from blisters applied behind or before the ear, or by a hot iron touching the antihelix of the ear. By this communication or connexion possibly too it is, that a vibrating string, held between one’s teeth, gives a strong idea of sound to the person who holds it, which no body else can perceive. Perhaps too the dis- tribution of this nerve occasions the head to be so quick- ly turned upon the impression of sound in our ears. Eighth The Eighth Pair* of nerves rise from the lateral pair. bases of the corpora olivaria in disgregated fibres; and! as they are entering the anterior internal part of the holes common to the os occipitis and temporum, each is joined by a nerve which ascends within the dura mate/]- from the tenth of the head, the first, second, and inferior | cervical nerves: This, every body knows, has the name of the Nervus Accessorius. When the two get out of the skull, the accessorius separates from the eighth^ and, descending obliquely outwards, passes througl theslerno-mastoideusnm&cie, to which it gives branchi es, and afterwards terminates in the trapezius and rhomboid muscles of the scapida. In this course it isi generally more or less joined by the second cervical nerve. Why this nerve, and several others which art:' distributed to muscles, are made to pierce througbi muscles, which they might have passed only near tflji I do not know. The large eighth pair, soon after its exit, give# t adheres closely si way, runs straight down the neck behind the intern^ jugular vein, and at the external side of the carotid m tery. As it is about to enter the thorax, a large nervje goes off from the eighth of each side. This branch of 1 the right side turns round from the fere to the bade 1' ■ part of the subclavian artery, while the branch of the left side turns round the great curve of the aorta, and - both of them mounting up again at the side of thfi '' * Par vagum, Pnemc-gastricus.—E. -I- Glcsso pharyngei.®*-' OF THE PARTICULAR NERVES. oesophagus, to which they give branches, are lost at last in the larynx. These are called the Recurrent Recurrent nerves, which we are desired to shun in the operation nerve*, of bronchotomy, though their deep situation protects them sufficiently. The muscles of the larynx being in a good measure supplied with nerves from the recur- rents, it is to be expected, that the cutting of them will greatly weaken the voice, though it will not be entirely ost, so long as the superior branches of the eighth pair a are entire. Why the recurrent nerves rise so low from the eighth pair, to go round a large artery, and to have 11 such a long course upwards, I know not. The eighth pair, above, and at or near the place 1 where the recurrent nerves go off from it, or frequent- ly the recurrents themselves, send off small nerves to k the pericardium, and to join with the branches of the l intercostal that are distributed to the heart; but their « size and situation are uncertain. ! After these branches are sent off, the par vagum on oi each side descends behind the great branch of the tra- v chea, and gives numerous filaments to the lungs, and n somesf the to left the side heart running in going on the to thefore-part oesophagus. of the oesopha-The one ii 1 278 OF THE PARTICULAR NERVES. ward to the internal side of the os pisiforme of the wrist; where it sends off a branch which sinks under the large tendons in the palm, to go across to the other side of the wrist, serving the musculi lumbricales and inlerossei, and at last terminating in the short muscles of the thumb and fore-finger. What remains of the ulnar nerve, after supplying the short muscles of the little finger, divides into three branches; whereof two are extended along the side of the sheath of the ten- dons of the flexors of the little finger, to furnish the concave side of that finger ; and the third branch is dis- posed in the same way upon the side of the ring-finger next to the little-finger. When we lean or press on the internal condyle of * the os humeri, the numbness and prickling we fre- | quently feel, point out the course of this nerve. I have seen a weakness and atrophy in the parts which I men- . tioned as supplied by this nerve after a wound in the internal lower part of the arm («). Radialis. 7- Radialis * accompanies the humeral artery to >; the bending of the elbow, serving the flexors of the cubit in its way ; then passing through the pronator radii teres muscle, it gives nerves to the muscles on the fore-part ot the fore-arm, and continues its course near to the radius, bestowing branches on the circum- j jacent muscles. Near the wrist, it sometimes gives off a nerve which is distributed to the back of the hand, and the convex part of the thumb and several of the fingers, instead of the branch of the muscular. The5, larger part of this nerve, passing behind the annular!, ligament of the wrist, gives nerves to the short mus- cles of the thumb; and afterwards sends a branch • along each side of the sheath of the tendons of the flex- ors of the thumb, fore-finger, mid-finger, andone branch to the side of the ring-finger, next to the middle one, to be lost on the concave side of those fingers (6). Though the radial nerve passes through the pronator muscle, and the muscular nerve seems to be still more (*а ) Monro,Median Nerv.of Winslow.—E. Syst. p. 136. tab. xvi E. (б) Monro, Nerv. Syst. p. 138. tab. xviii.—E. OF THE PARTICOLAR NERVES. 279 unfavourably placed within the supinator brevis ; yet -fc the action of these muscles does not seem to have any i!1 effect in hindering the influence of these nerves, for a the fingers or hand can be bended while pronation is | performing vigorously, and they can be extended while 1 supination is exercised. . The manner of the going off of these nerves of the I fingers, both from the ulnar and radial, is, that a single e branch is sent from the trunk to the side of the thumb ) and little-finger farthest from the other fingers; and ill the rest are supplied by a trunk of a nerve which . END OF THE ANATOMY OF THE NERVES. THE DESCRIPTION OF THE HUMAN LACTEAL SAC AND DUCT* The receptaculum chyli of Pecquet, or saccus lacteusii Van Horne, is a membranous somewhat pyriform baj two thirds of an inch long, one-third of an inch over I its largest part when collapsed; situated on the firf vertebra of the loins to the right of the aorta, a littl higher than the right emulgent artery, behind the rijj inferior muscle of the diaphragm ; it is formed by tli union of three tubes, one from under the aorta, tH second from the interstice of the aorta and cava, tb third from under the emulgens of the right side. Tb lacteal sac, becoming gradually smaller towards b upper part, is contracted into a slender membranou pipe, of about a line diameter, which is generally nan: ed the Thoracic Duct. This passes betwixt the mus cular appendices or inferior muscles of the diaphrajw on the right of, and somewhat behind the aorta; ther being lodged in the cellular substance behind tb pleura, it mounts between the aorta and the vena azygos as far as the fifth vertebra of the thorax, where it i hid by the azygos, as this vein rises forwards to joi OF THE LACTEAL SAC AND DUCT. 285 descending or superior cava; after which the duct es obliquely over to the left side behind the oeso- yus, aorta descendens, and the great curvature of aorta, until it reaches the left carotid artery; be- ! ind which, on the left side of the oesophagus, it runs I > the interstice of the first and second vertebra of the j1 \.orax, where it begins to separate from the carotid, fetching farther towards the left internal jugular vein r y a circular turn, whose convex part is uppermost. t the top of this arch it splits into two for a line and s half; the superior branch receiving into it a large J mphatic vessel from the cervical glands. This lym- i hatic appears, by blowing air and injecting liquors < ito it, to have few valves. When the two branches E-e again united, the duct continues its course towards le internal jugular vein, behind which it descends, . I id, immediately at the left side of the insertion of this ji| nn,avian enters vein, the whose superior internal posterior membrane part of theduplicated, left sub- ri rms a semilunar valve that is convex externally, and e >vers two-thirds of the orifice at the duct; imme- s ately below this orifice, a cervical vein from the mus- i li scaleni enters the subclavian, f The coats of the sac and duct are thin transparent .1 embranes; from the inside of which, in the duct, 11 lall semilunar valves are produced, most commonly ij pairs ; which are so situated as to allow the passage p liquors upwards, but oppose their return in an op- !•;'] site course. The number of these is generally ten twelve. 1 i This is the most simple and common course, situa- ; n, and structure, of the receptaculum chyli and tho- • si cic duct; but having had occasion to observe a variety 1 1 these parts, of different subjects, I shall set down r« e most remarkable of them. - iqlThe sac is sometimes situated lower down than in ^Hmsions;■fe former description;is not composed is not of always the same of the number same di- of < iMcts; and frequently appears to consist of several mall cells or ducts, instead of being one simple cavity, i iajThe diameter of the duct is various in most bodies, f and is seldom uniform in the same subject; but fre- OF THE LACTEAL SAC AND DUCT. quently sudden enlargements or sacculi of it are ob servable. The divisions which authors mention of th« duct are very uncertain. 1 have seen it divided inti| two, whereof one branch climbed over the fore-part dl the aorta at the eight vertebra of the thorax, and at tin fifth slipped behind that artery, to join the other brand which continued in the ordinary course. The precis* vertebra, where it begins to turn to the left side, | also uncertain. Frequently it does not split at its su- perior arch; in which case a large sac is found near ifi aperture into the subclavian vein. Generally it ha! but one orifice; though I have seen two in one bodjj and three in another: Nay, sometimes it divides into two, under the curvature of the great artery: one goA to the right, another to the left subclavian vein; ail I have found this duct discharging itself entirely into the right subclavian. The lymphatic vessel which ew ters its superior arch, is often sent from the thyrovt gland (a). Is not the situation of the receptaculvm chyli, si much nearer the muscular appendices of the diaphragll | in men than in brutes, designed to supply the disad, « ourvantageous erect posture course ? the chyle must otherwise have hi K! Do not the descent of the end of the duct to the subclavian vein, and the opening of the lymphatic in- s to the top of the arch, contribute to the ready admifri1 sion of the chyle into that vein ? (a) See Cruickshank’s Anatomy of the absorbent Vessels.—]fl ^ SUPPLEMENT, CONTAINING A ASCRIPTION OF THE OSSEOUS STRUCTURE OF THE INTERNAL EAR (a). BY THE EDITOR. Although the celebrated author of the foregoing mges has thought proper to omit a description of the t >ony structure of the internal ear, exhibited by a dis- t: ection of the petrous portion of the temporal bone, this il (mission is an evident deficiency in a work which, in i 11 other respects, is the most complete of its kind; I nd it has been judged proper, in the present edition, i o supply it by the following view. Q On carefully opening the petrous portion of the Meatus p emporal bone, we see within it certain cavities con- auditorms. a ainingsmall bones, and lined with membranes, on which i re expanded nervous filaments. This dissection may i; e made in two ways, according as we begin on the i! iteral or mesial side of the os petrosum. In this de- qi iription the former method is pursued. The exter- 1 al auditory passage, noticed at p. 67, runs inwards i i a curved direction, first rising coronad and glabellad, ad then turning basilad, where it terminates in a ng, into which is fixed a membrane called mem- vn rana tympani, as it is stretched over the first cavity t! Ice the head of a drum. Behind this membrane are .n :en, shining through it, some little bones, and, on (a) See p. 70. DESCRIPTION OP THE HUMAN EAR. carefully removing the membrane, the cavity of the tympanum is brought into view (n). Tympanum-and This so shallowcavity isas ofjust an toirregular contain hemisphericalbetween the mem-form, brane and the mesial side of the cavity the ossicula auditus. The cavity is furnished with several open- ings and holes, and a remarkable eminence. One of the openings is in the glabellar side, and leads to the eustachian tube, by which the tympanum communicates with the fauces. Another opening leads iniad to the cells of the mastoid process, and is closed with a bone, as will be presently described. Behind, or rather me~ siad of, the ossicula,axe two holes, theone coronad, call- ed fenestra ovalis, or the oval hole, the other basilad of| the former, and denominated /ewe^ra rotunda, or the round hole ; and both these holes are closed, the for- mer with a peculiar bone, the latter with a membrane The eminence mentioned above lies between thesi last two holes, and is called promontory (b). auditus.Ossicula whichThe areossicula articulated auditus together, consist of and four are very contiguous small bones t< the parts already noticed. They are denominated mal- leus, or the mallet ; incus, or the anvil; os obiculare, oi the spherical bone; and stapes, or the stirrup (c). Malleus. is situatedThe Malleus contiguous is the tolargest the membranaof the four tympani. bones, andIt consists of a round head, which forms the greater part of the bone ; of a handle separated from the head by a neck, and of two processes. The head is most coroj nad, and the handle extends basilad and a little latej rad and glabellad, nearly opposite the middle of thi membrane, and placed at an obtuse angle with thl neck. One of the processes, called, after Raw, prdi cessus Ravianus, rises from the neck of the bone, is long and slender, and stretches glabellad and laterad to the fissure in the articular cavity of the temporal bone. The other, or short process, is nearly a con- tinuation of the handle, and rises coronad to near the coronal edge of the tympanum. The former gives in- sertion to the muscle called externus mallei, and into (a) Alton. Acad. An not. lib. iv. tab. i. Fig. 1. (c)(A) Alton,Alton. Acad.loc: citat. Annot. Fig. lib.3. Mitchell, iv. tab. 1.Engrav. Fig. 3. PI. vi DESCRIPTION OF THE INTERNAL EAR. 289 the handle are inserted two muscles, the laxator tym- mni and the tensor tympani. The malleus is connected by ginglymus with the lext bone by the round head, which is covered with i ;artilage, and by its long process with the body of the ;emporal bone, while its handle is attached by an in- ;ermediate membrane to the membrana tympani. It s perfectly ossified in a fetus of nine months. Its mncipal use is to act as a lever for enabling the mus- ;les attached to it, to increase or diminish the tension )f the membrana tympani, and thus modify the sounds ir impulses of the air, which strike upon the latter ; mt from the solidity of its texture, it must, like the ither ossicula, contribute materially to the propagation >f those sounds towards the most internal cavities of j he.organ of hearing. Its motions will be better un- I lerstood after describing its articulation with the next tone (a). ' i The incus, not less aptly named from its figure and incus. ij onnexion with the malleus than this latter bone, is t i! he next in point of size. It is composed of a body I nd two processes. The body is broad, and has a re- U larkable hollow, containing a furrow and linear nijminences corresponding to similar inequalities of sur- ikce on the head of the malleus. Round the edge of niis hollow the bone is scabrous, where a capsular liga- tjnent is attached for securing the articulation with the One of the processes is longer and more taper- t ig than the other, and runs basilad and a little cen- |l ad, but nearly parallel to the handle of the malleus, j id has at its extremity a slight depression for its arti- j Ration with the next bone. The shorter process is II tuated in nearly a horizontal position, extending i iad and centrad, within a sinus of the os petrosum i the mastoid cells. In its substance the incus re- i imbles the other ossicula. Its connexions may be adily understood from the above description and the j dative situation of its several parts (6). Ka) Mitchell, Engrav. PI. viii. fig. 11, 15, 19. lei tchell,b) Albin. Engrav. Acad. PI. Ann. viii. lib.fig. IV.12, 16,Tab. and I. 19.fig. 2. Tab. II. fig. 6. 290 DESCRIPTION OF THE INTERNAL EAR. Motions. The incus either has no motion, or one that is verfi circumscribed, and its only use seems to be to assist! in the propagation of sounds; but the motions of the; malleus are less confined. Its head indeed is so arti- culated with the incus, as to admit of motion only in two directions, that is, in the direction of the grooves and prominences. Its principal moving part is the handle, which, by the various muscles attached to the bone, can be moved to either side, and rotated a little on its axis; and being closely connected with the mem-* brana tympuni, must carry that membrane with it, so as to stretch or relax it, and thus increase or diminislfc the intensity of sounds. Hence, a thickening or in- duration of the membrane, a rupture of that mem-* brane, or a loss of the malleus, by internal suppura- tion, though /seldom productive of total deafness, ma- terially impedes the sense of hearing. Hence too, in partial deafness occasioned by the first cause, a per- foration of the membrane, though it cannot restore j its mobility, often improves the faculty, by admitting ^ the pulses of the air to the ossicula (a). lure.On Orbicu. hearing,The os and orbiculare indeed isof thethe smallestwhole body. of the It bones is not of ip perfectly spherical, but is a little flattened on one side, j,, and more convex on the other; it lies immediately between the extremity of the long process of the incus ,■ and the head of the stapes, so as to form a connecting ^ link in the chain of bones, and this seems to be its on- ly use. It is secured in its situation by ligament {b). . ' Stapes. The last bone of the tympanum bears an apt resem«i: ^ blance to a stirrup, having a small head, two side pro** i, cesses or legs, and a foot. It is placed nearly perpen~ , dicular to the long process of the incus, with its foot , resting on the back of the tympanum and filling up . the oval hole. Its head has a spherical hollow, for re- , ceiving the central surface of the preceding bone; its legs are curved but of unequal lengths, that on the inial side of the tympanum being larger and more . curved. These legs are united together by a dense membrane, which is fixed to the hollow of the foot. (a)\b) AstleyMitchell, Cooper, Engrav. Philos. Plate Trans. viii. fig. 1801, 14,16, p. 435. 18. DESCRIPTION OF THE INTERNAL EAR. 291 This last part is of an oval form, corresponding to the figure of the whole which it fills up. The foot is not I entirely bony, but its centre is occupied by a mem- brane forming part of the partition between the tym- panum and the central cavity of the ear. Between the neck and the legs, on the inial and coronal part, is in- serted the muscle called stapedius, by which the inial leg of the bone is moved centrad, and a little coronad, i ind the other leg is of course turned in opposite direc- tions. The use of this bone is chiefly to communi- ite sounds through thefenestra ovalis to the labyrinth, md by its mobility it probably stretches the mem- >rane contained within its foot, so as to increase the Intensity of the sound. This bone seems to be the a nost essential of the ossicula, as it has been remarked Ji hat while it remains, though the other bones have H >een destroyed, the hearing is not entirely lost, and \ aay even be improved by time (a). i| The central plate of the tympanum, may be said to Labyrinth. iS orm the peripheral or lateral plate of the cavity which 1 ies immediately behind it, and is obscurely marked d dth some of the eminences and depressions that bound i i lis cavity; but to bring the parts of the labyrinth : ji lore completely into view, it is necessary to cut and t le away the back-part of the tympanum, when we come ;t > a very complex cavity, called from that circumstance ibyrinth, consisting of three principal divisions, the ’.stibule, the cochlea, and the semicircular canals. The Wchlea is situated most glabellad and mesiad; the se- ^•(ilieircular canals, most iniad and laterad, and the ves- I bule occupies the centre between them (6)'. It must *k9 5 remarked, that in their natural situation, these ca- a ties are hollowed out within the substance of the os : '.trosum, and have not the external form in which they - : e usually represented in anatomical engravings, till ..■ e surrounding parts have been removed by the instru- ents of the dissector. Within the vestibule are seen several holes or open- Vestibule. £■' ( (a) Mitchell, Engrav. Plate viii. fig. 13, 17, 18- av.(6) PlateAlbin. viii. Acad. fig. Ann.20, 21. lib. iv. tab. 1. fig. 5. Mitchell, En- 292 DESCRIPTION OF THE INTERNAL EAR. ings. One of these openings is situated laterad, and is the oval hole leading from the tympanum ; five others towards the inial side of the vestibule lead to the three semicircular canals. Anothe ' 1 to part of the cochlea, is seen on and several other holes and a spongy cribriform plate, the central or mesial side of the vestibule, lead to- wards the cavity of the cranium, to give passage to ves- ■ sels and nervous filaments from that cavity. Semicircu-lar canal, fromThere their are positions, three semicircularsuperior, horizontal, canals, denominatedand verticals Each of these canals at one extremity, opens into the vestibule by a separate hole, and the superior canal hasi also a separate opening at the other extremity, buti the other two, before terminating in the vestibule, unite1 into one canal, and form a Common orifice. The inte- rior of each of these bony canals, as well as the other: cavities, is lined with a membrane which is also hoi- to low. These hollow membranes are sometimes called ^ the membranous canals (a). 1 Coddea. theThe inside cochlea of the is shell a double of a periwinkle: spiral cavity, its structureresembling! is: f not easily described in words. If we suppose a pretty ?f long hollow cone, divided longitudinally by a parti- tion on one side, that reaches nearly to the point, toi be wrapped spirally round a central pillar, (also:1 formed of a short hollow cone) so as to make two turns. and a half, and still preserve its conical shape, we shall: n have a tolerably correct idea of the internal structure of the cochlea. The spiral turns supposed to be made: by the larger cone are called scalce, from their fancied! resemblance to a winding stair-case. One of these: scalae opens directly into the vestibule, by the holes: already mentioned, and is therefore called scala vesti- bull, but the other reaches to the tympanum, and forms: the round hole described under that cavity. It is: called scala tyrnpani. The partition that divides the two spiral cavities from each other, is caMed. lamina spira- lis or the spiral plate, and in the recent state is com- 4, (a)5. Albin,Mitchell, Ann. Engrav. Acad.lib. plate iv. viii. tab. fig.1. fig.20, 5,21. 6. tab. 2. fig. 2,3,; DESCRIPTION OF THE INTERNAL EAR. 293 posed of a spongy bony plate next the central pillar, and a membrane stretching from its edge, to the op- posite side of the cavity. The short cone which forms the central pillar is called modiolus, and above this is a funnel-shaped cavity, thence called infundibulum, ap- pearing like another cone, joining the former, point to point, and communicating with it. Here the spiral date is deficient, so that the spiral canals of the coch- ea communicate together at the infundibulum. All the cavities now described are lined with a fibrous membrane, constituting their internal 'periosteum' and the interstices are filled with a watery liquor, which sometimes coagulates or is inspissated so as to prevent the propagation of sounds within these internal cavi- ties, and thus produce total deafness. Besides the openings already mentioned, there are two conical sinuses that pass through the os petrosum to its central surface within the skull, and terminate there in small triangular orifices on each side of the internal auditory passage. These are denominated aquceductus cochlece, and aquceductus vestibuli, as they were supposed by Cotunnius to carry off the superflu- ous water of the labyrinth. Their use seems not to be well understood (a). the(a) Brain, On thisEye subject and Ear; see Scarpa,Valsalva, De De Olfact. Aure et Humana; Audit.; Soemmer-Monro on -*''•ing, Abbildung.Human Ear. des Menslich; Hoerorganes, and Saunders’ Anat. 1 '• INDEX. A. i ; AccessoryAbductor nerve, nerves, 268. 264. AcetabulumAnalysis, chemical, of ossa innominata,of bones, 11. 150. i Apophyses,Acoustic or theirauditory different nerve, sorts, 267. uses, 18. Many so named are ] Appendices,epiphyses, vid.19. Epiphyses, i lArm-bone,.rthrodia, 30,vid. 32.humeri os. i; jI Articulations,Articular nerve, 28. 276. Symphysis, 29. Synarthrosis, ib. Diarthro- i Astragalus,sis, 30, 32. 222. Dispute Its articulation, concerning them,223. 31.Of children, 224. i ii Atlas,Axis, oror thirdthe first vertebra vertebra colli, of 132. the neck, 127. Of infants, 128. Blood, motion of within the head,B 225. Bones,celli, what,ib. Arteries, 4. Their 7- plates,Veins, ib.8. Fibres,Nerves, claviculi, ib. Circulation 5. Can- of andtheir diseases, liquors, 9,nourishment, 15. Transverse increase, canals, decrease, 9. Longitudinal 9. Phenomena ones, ib.Distinguished Analysis, into11. broadPeriosteum and round, internum, 16. Strengthib. Marrow, increased 13. 20.by beingOssification, hollow, ib.21. Processes,Phenomena, 18. 25.Cavities, Articulations, 19. Epiphyses 28. Breast bone,64. vid. Sternum, Broad bones, their structure, 16.C. CancelliCalcis os, of 213. bones, Of 5. children, Corrugati, 214. cribriformes, reticulares, uses, Caniniib. dentes, 113, INDEX. Carpus, consists of eight bones, 184. Its figure, substance, ar- Cartilages,ticulation, what; motions, their 188. plates, Uses; fibres, of 36. infants, Vessels, 189. 37- Nerves,, Cavitiesib. Ossification, of bones, their how different prevented, kinds, ib. 19Their ; uses, uses, ibid. diseases, 38. CervicalDentata, vertebrae, 128. Axis,their distinguishing132. Seventh, marks, ibid. 125. Atlas, 127. Clavicles,Cheek-bones, 166. vid. Internal Malarum end, ossa. ib. Body, 167. External end, medullaryuses, 168. vessels, ib. Substance, articulation, of children ClaviculiCoccygis os,of bones,141. Itsperpendicular, first bone, ib. oblique, Its 2d, headed, 3d, 4th crooked, bones, 142.5. Collar-bone,Substance, vid. motion, Clavicle. diseases, uses, 143. CorticalCoronal suture,part of the48. encephalon most vascular, 225. Cranium,Costae, vid. its Ribs. figure, 45. Surfaces, ib. Tables, diploe, 47. Con- ib.sists of six proper, ib. and two common bones, 48. Its sutures, Crural nerves, posterior,anterior, 28. Cubitus,Cuboides vid.os, 215.Fore-arm. Cuneiforme os,ossa, of ofthe the wrist, foot, 185.externum, 215.'medium internum, 1 Cutaneous216. nerve, 276. Dentata, or 2d vertebra of theD. neck, 128. its distinguishing Dentes,marks, vid. ibid; Teeth. of infants, 130. Diarthrosis,dia, Ginglimus, 30, 32. ibid. Its three species, Enarthrosis, Arthro- DiploeDigiti, ofvid. the Fingers skull, 47.and Toes. Dorsalthey differvertebrae, from eachtheir other,distinguishing 134. marks, 132. Wherein Epiphyses,Enarthrosis, 20. 30, Several32. have epophyses, ibid. Their uses, ib. j EthmoidesEthmoidal suture,os. Its 52.cribriform plate. Nasal plate, 77- Cellulae ossaa child, spongiosa, 79. connexion, 78. Uses, morbid phenomena; of ExtremitiesFoot 210. inferior, 196. Consist, each, of thigh, ib. Leg, 201. 174. Fore-arm,superior, 178. 166. consist,Hand, 183.each, ofUses, shoulder, 195. ibid. Arm, INDEX. 297 'emale Composedskeleton, distinguishingof upper jaw, marks87. Lower of it, jaw,222. 104. Femorisend, 199. os, 196.Of infants, Its upper its articulation end, 197. andBody, motions, 198. 200. Lower 'ibula,articulation, its upper uses end, ; of204. infants, Body, 207- ib. Inferior end, 206. Its 'ingers,of middle, their annular, bones, phalanges,little linger, 194,1st, 195. ibid. 2d, 3d. Indicis, * ’oot,'ontanelle, composed 64. of tarsus, 210. Metatarsus, 217- Toes, 2J0. 'ore-arm,frontal-bone, 178. 54. ConsistsIts external of Ulna, surface, ibid. 55. Radius, Processes, 180. ibid. Ca- vities,58. Substance, ibid. Foramina, ibid Sinuses,56. Internal 59. Connexion,surface, 57- 60.Foramen, Uses; of children, 61. G linglimus,glions, nervous,its species, 228, 30, 256. 33. 1 Hosso-pharyngeal nerves, 268. ' mphosis, 30. H. d tland,gers, 183.192. Consists of carpus, 184. Metacarpus, 190. Fin- larmonia,launch-bones, 38. vid. Ilium ossa. leel-bone,lead, consists vid. of Calcis cranium, Os. 44. Face, 87- Its motions, 130. lumerilip-bone, os, vid. 174. Ischium Its upper Os. end, ibid. Body, lower end, 175. AHyoidesSubstance, os.; articulation,Its body; Cornua, motion, 117- 177. Appendices; Of children, Ligaments, 178. •< lypoglossisubstance, nervi, connexion, 270. uses ; of children, 113. . aw, lower, vid. Maxilla inferior.L ium— upper,ossa; Spine,87- dorsum, 144. External surface, ibid. Inte- rioribid. surface, 146. Medullary vessels, substance: of a child, o ncisoresnnominata dentes, ossa, 112.143. Composed of os ilium, 144. Ischium, lum,147. 150.Pubis, In 148. infants, Their Connexion, great foramen, 151. Phenomena, 149. Acetabu- Uses, Intercostal152. nerves, 266 and 271. schiuminfants, os, 148. 147. Processes, depressions, tuber, substance; of INDEX. L. Lattice-workLambdoid suture, of bones, 48. vid.Its additamenta,Cancelli. ibid. Leg,articulation composed andof Tibia, motions, 201. 209. Fibula, 204. Rotula, 207- Its Ligaments,eases, 36. 34.Uses, Their phenomena, fibres, ibid. ib. Vessels, nerves, ibid. Dis- LumbarLinguales vertebrae, nervi, 270. their particular structure, 135. Differences, Lunare136. os, 185. Magnum os of the wrist, 187. M. Malarumnexion ;ossa, of infants,their processes, 93. 92. Holes, ib. Substance, con- Marrow,nerves, what,ibid. 13.Diseases, Its chemical 14. Transverse analysis, ibid.and longitudinalIts arteries, canalsveins, Maxillafor conveying inferior, it, 104.10. Uses,Sides, 14. base, Phenomena 105. Angles, and diseases, processes, 16. foramina,infants, 108. 106. Uses,Substance, 109. Articulation, Motions, 107. Of ibid.- superior consists of 13 bones, 87. Their connexion, , Maxillaria95. Sinuses, ossa, their 96. processes,Morbid phenomena, 93. Depressions, Substance, 94. Foramina,97- Con- Maxillarynexion, nerve,Uses; ofinferior, children, 263, . Medulla cerebral,- superior, fibrous, 226.262. Metacarpus,articulation, composed ibid. Figure, of four uses,bones, digiti 190. indicis.Substance, Medii, at birth, 191. Metatarsus,Annularis, composed minimi, of192. five bones, Pollicis, 218. 1, 2, 3, ibid. Molares4, 119. dentes, 113. MotoresMotion, muscular,oculi, nervi, 252. 275. Mucilaginouscellular substance, glands, vessels,39. Liquor nerves, secreted 40. byDiseases, them, 40.41. TheirUses, MuscularPhenomena, spiral ibid. nerve, 277- Musculo cutaneous nerve, 277* N. NaviculareNasi ossi, their os, of sides, the tarsus,90. Connexion, 214. uses; of an infant, ibid, Nerves,Neck, vid. fibrous Cervical texture vertebrae. of, 226. Extreme tenuity, 227; glions,Coats, ibid.Vessels, Extreme 228. Inelastic, fibrils pulpy, ibid. 229.Ramification, Not confound- Gan- INDEX. 299 iI sensationed, ibid. andMorbid motion, changes, ibid. Objections230, 231. answered,The instruments 231. Ac- of ■1i rebral,tion of, how257- produced,Spinal, 235.273. ArteriousCervical, and274. venous, Dorsal, 241. 279.Ce- ' ervousLumbar, action, 280. hypothesis of, 233. Vibration, ibid. Nervous i ervousfluid, 235.fluid, source of, 235. Nature of, 242. Compared . i I utrition,with other nervous, secreted considered, fluids, 243. 230. O. bturator nerves, 281. ccipitissurface, os, 73. 7L Holes,Its external 74. Substance, surface, Processes, Connexion, ibid. 75- Internal Uses, Ii [factoryin infants, nerves, 76. 257* pticpthalmic nerves, nerves, 258. 261. ssificationsition of vessels, of bones, and 21. from Accounted pressure, 22,for from25. particularPhenomena, dispo- 25, 121.steogenea, Its history, its history, ib. 27. Of what use, 28. P. aj 1alati Nasal os, lamella,98. Its Orbitar square process, palate plate,100. PterygoidSubstance, Process, connexion, 99. an4 Iar uses, vagum of children; nervorum. diseases, 269. 101. b1 arietalibid. bones,Substance, their connexion,external surface, uses, 62.63. InternalOf children, surface, 64. eI ttella,Practical vid. observations Rotula. concerning bregma, ibid. ; As athetic:lvis, 143. nerves, Consists 261. of os sacrum, 137. Coccygis, 141. Ossa rI ;richondrium,innominata, 143. its vessels, 37. via iriosteumnerves, 3, externum, Uses, ibid. 1. ItsDiseases, fibres, ibid.4. Arteries, 2. Veins, -jj.s lalanges—internum, of the fingers, its structure,194. 11. Uses, 12. a- irenic nerves, t275.oes, 219. rav atessiforme of bones,os of thetheir wrist, fibres, 186. 4. 1- dlicis pmanusedis ossa, ossa, vid. vid. Toes. Thumb. oi >rtio mollis,dura of 267- the seventh pair of nerves, 267. » ibis■ocesses os, 148.of bones, Substance; vid. Apophyses. of children, 149. 300 INDEX. Radial nerve, 278. R. Radius,dren, itsarticulation, upper end, 182. 181. Body; lower end, ibid. Of chill RecurrentReceptaculum nerves, chyli, 269. 284. Ribs,Retina, 153. 259. Their middle posterior end, 154. Anterior end Differsubstance, from cartilages,each other, 155. ibid. ArticulationDistinguished and into motion, true 156an< false,5th, 6th, 156. 7th, Distinguishing 11th, 12th, 159. marks Of ofinfants, the 1st,160 2d, 3d, 4th Rotuladren, 208.described, its substance, 207- Articulation; of chill Roundibid. Bones, their structure, 16. Strength, how increased! S. ; Sacrum os, its body, 137. Processes, oblique, transverse, 138 ofCanal, children, Foramina, 141. 139. Substance, articulation, 140. Uses; ScaphoidSagittal suture, bone of 49. the wrist, 185. Scapula,anterior its surface, base, 169. 170. Inferior Processes, costa, spine, superior 171- costa, Acromion, dorsum; 'j. coracoidsels, substance, process, articulation, 171. Third 172. process, Uses, 172. of children,Medullary 173. ves« Schyndelesis,Scapular nerve, SO. 276. SciaticSensation, nerve, '248. 281. SesamoidSharebone, bones, vid. Ossahow formed,pubis. 280. Where found, ibid. ShoulderShoulder-blade, consists vid. of clavicle,scapula. 166. and scapula 169. Skeleton,Sinus frontales, natural, 59. artificial,Sphenoidal, 43. 85.Situation Maxillary, of the 96. bones, 44.. - 166.Divided Inferior, into head, 196. ibid. Trunk, 118. Extremities superiorii ‘ Skull, vid.of a Cranium.female, its differences from that of the male, 222. , SphenoidInternal bone, surface, its external 82. Holessurface, proper, processes, 83. 80. Common,Cavities, 84.81. , SphenoidalSinuses, 85.suture, Substance, 52. connexion, uses of children, 86. > Spine,137. its shape, 118. Consists of true vertebra, ibid, and false, . Spongiosauses ; of inferiora children 102.ossa, 101. Their substance, connexion^ I INDEX. 301 i: SpongiosaIquamous superiorasutures, 50. ossa, How78. formed, 51. j ternum,Xiphoid 160. cartilage, Its substance, 162. Diseases, 161. First 163. bone, Connexion ib. Second ; of bone. chil- •ub-occipitaldren ; uses, nerves, motion, 270. 164. j iutures, of29. the Howcranium, formed, 48. ibid.Coronal, lambdoid, ibid. Sagittal, . matic,49. Squamous, 52. Uses, 50. 53. Ethmoidal, sphenoidal, transverse, zygo- j Sympathetic■■ of the nerves, face, distinguished great, 266, 271. by names, 88. Uses, 89. lymphysis, divided intolesser, synchondrosis, 267 syneurosis, syssarcosis, 29. i lynarthrosis,lesis, 29. divided into suture, harmonia, gomphosis, schynde- : lyneurosis,ynchondrosis, ibid. ibid, i iyssarcosis,iynovia of joints, 29. of what composed, 40. Its uses, diseases, 41. Parsus consists of seven bones, 210.T. Its articulation, 217- Uses, 217- feeth,sels, their110. base,Formation, roots, periosteum, shedding, substance,111. Connexion, 109. Canals, uses, 112.ves- Uj DistinguishedPhenomena, 115. into incisores, ibid. Canini, molares, 113. BTemporalCavities, bones, 66. Holes,65. Their 67- externalInternal surface,surface, processes,68. Processes, ibid. infants,ibid. Cavities, 70. holes, 69. Substance, connexion, uses ; of ThoracicThigh bone, duct, vid. 284. Femoris os. Thorax,160. 153.Its motion, Consists 164. of vertebrae, 132. Ribs, 153. Sternum, ThumbAt the consists time ofof birth, three ibid.bones ;Second the first, bone, its ibid. articulation, Its articula- 193. Tibia,tion, its 194. upper Third end, bone,cartilages, ibid. 201. Body, 202. Lower end, Toes,203. 219, Articulation; differ from theof children,fingers, uses; 204. of children, 220. TrapeziumTransverse os,suture, 186. 52. TrapezoidesTriquetra ossa, os, 48.187* TrunkTrochoides of the Ginglimus, Skeleton, 33.consists of the spine, 119. Pelvis, 143. TurbinataThorax, ossa,153. vid. Spongiosa. INDEX. U. Ulna,of children, its upper 180. end, 178. Body, 179. Lower end, articulation) UncifonneUlnar nerve, os 277-of the wrist, 187- UnguisMorbid ossa, Phenomena; their surfaces, of children, 90. Substance, 91. connexion, uses . V ■ Vertebrae Dorsal,Cervical, vid. vid. Dorsal. Cervical. Lumbar,false, composed vid. Lumbar. of os sacrum, 13J- Coccygis, 141- cesses, ligaments,true, 119. foramina,Their bodies, 121. ibid.Articulations, Cai-tilages, phenomena,120. Pro4 Dorsal,122. Of 132. infants, Lumbar, diseases, 135. Uses,124. securedDivided from into luxations, cervical, ibid.,136. Vesselsof ligaments, of periosteum, 34; cartilages, 4; of the 37 bones, ; mucilaginous 7 5 of the glands,marrow, 39. 13 }| Vomer,Vibration, 102. nervous, Its figure, considered, situation, 233. 103. Substance, connexion,, uses, 104. W. Women, the differences of their bones from those of men, 222. WormanaWrist, vid. ossa, Carpus. vid. Triquetra. Xiphoid cartilage, 162. Its diseases, 163. Zygoma,Zygomatic 65. suture, 52. Printed by EdinbubghJames Clarke : and Co. 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INSTITUTIONS of MEDICINAL PA- HERDMAN on WHITE-SWELLING of the JOINT& 8vo. i , ■< '. , ■ i i.... . _ in PLATE I. | Representing the Front View of the Male Skeleton, with some of the Cartilages and Ligaments which i connect the Bones to each other. HEAD AND NECK. 4. Os Frontis, or Frontal Bone. B. The Parietal Bone. Z. Temporal Process of the Sphenoid Bone. D. Squamous part of the Temporal Bone, i E. Mastoid Process of that Bone. P. The Superior Maxillary Bone. 3. The Nasal Bone. ,Ff.r Malar, or Cheek Bone. ; . The Lower Jaw. TRUNK. i. The Sternum. . B.7. — CartilagesSeventh, or of last the TrueRibs. Rib. ID. — Twelfth, or last False Rib. E. — Cartilages,Lumbar Vertebrae, and Transverse with theirProcesses. Intervertebral \F.3. — Os Sacrum.Innominatum, composed of [. — Os Ilium.Pubis. — Os Ischium. SUPERIOR EXTREMITY. 4. The Clavicle. * iB. Inner Surface of the Scapula. . The Acromion of the Scapula. . The Coracoid Process of that Bone. PLATE I. C. The Os Humeri. d. The Head, or Ball of the Os Humeri. e. Internal Tubercle of the Os Humeri; and, farthei out, the Groove for Lodging the Tendon of th« Long Head of the Biceps Muscle. e. The Inner, and *1 The Outer Condyle of the Os Humeri. Betwee* e and f, the Hollow for Lodging the Coronoic Process of the Ulna in the Flexion of the Forej arm. 1). The Radius. g. — Head of the Radius. E. — Ulna. h. — Coronoid Process of the Ulna. F. — Bones of the Carpus. G. — Metacarpal Bone of the Thumb. H. — Metacarpal Bones of the Fingers. 7. — Two Bones of the Thumb. K. — Three Phalanges of the Fingers. Inferior Extremity. A. Os Femoris. d. The Ball, or Head of this Bone, lodged in the! Acetabulum. e. The Cervix of the Bone. f. — Large Trochanter. g. — Small Trochanter. h. — Inner Condyle. B. — Patella, placed upon the Trochlea of the OSi Femoris. C. — Tibia. k. — Head of the Tibia, between which and the Condyles of the os Femoris, the Semi-lunar Cartilages appear. I. — Tubercle of the Tibia. m. — Malleolus Internus. D. — Fibula, the upper end of which is connected with the Tibia. n. — Malleolus Externus. E. — Bones of the Tarsus. o. — Projection of the Os Calcis. F Metatarsal Bones. G. — Phalanges of the Toes. PLATE II. ■Representing the Back View of the Male Skeleton, with some of the Cartilages and Ligaments which connect the Bones to each other. HEAD AND TRUNK. A. The Parietal Bone. a. — Sagittal Suture and Parietal Hole. B. — Occipital Bone. h,b Lambdoid Suture. C. — joining of the Temporal and Parietal Bones. D. — Cheek Bone. E. F. The Inner or Back Part of the Jaws, with the Teeth G. The first Cervical Vertebra. H. — second Cervical Vertebra. I. — seventh Cervical Vertebra. c. — Spinous Processes of the Cervical Vertebrae. K. — first Dorsal Vertebra. L. — Twelfth Dorsal Vertebra. d. — Spinous Processes of the Dorsal Vertebra. e. Their Transverse Processes. M. The first Lumbar Vertebra. N. The fifth Lumbar Vertebra. f. Their Spinous, and g. Their Transverse Processes. N. The Os Sacrum. h. The uppermost spinous Process. Farther out are seen the Superior Oblique Processes of this bone, joined to the Inferior Oblique of the last Lum- bar Vertebra. i. i. The lateral parts of the Os Sacrum, joined to the Ossa Innominata. k. An opening in the under and back part of this bone, covered in the Subject by a Ligamentous Membrane. * p 3 PLATE II. P. The Os Coccygis, joined by its shoulders to the I Os Sacrum at the lower part of the opening k. Q. The Os Ilium. R. The Os Pubis. S. The Os Ischium. T. U. The seven True Ribs. V. V. The five False Ribs. SUPERIOR EXTREMITY. A. The Clavicle. B. The Dorsum Scapulae. a. The Spine of the Scapula. b. The Acromion of the Scapula. c. A Fossa for lodging the Supra-spinatus Muscle. d. An irregular surface, occupied by the Infra-spi- natus Muscle. C. The Os Humeri. e. The Ball of the Os Humeri. f. The External Tubercle of the Bone. g. The External Condyle. h. The Internal Condyle. i. Cavity for lodging the Olecranon of the Ulna. D. The Radius. k. The head of the Radius articulated with the Troch- lea of the Os Humeri. l. The under end of the Radius, grooved by the ten- dons of the Muscles. E. The Ulna m. — Olecranon of the Ulna. n. The under end of the Ulna, withits Styloid Process. F- — Bones of the Carpus. G. — Metacarpal Bone of the Thumb. H. — Metacarpal Bone of the Fingers. L- — two Bones of the Thumb. K. — three Phalanges of the Fingers. INFERIOR EXTREMITY. A. The Os Femoris. a. Part of the Ball of the Os Femoris. b. The Cervix of the Bone. c. The Trochanter Major. PLATE III. Id. The Trochanter Minor. e. — cavity for lodging the Popliteal Vessels and Nerves. f. — External Condyle. g. —. Internal Condyle. «. — Semi-lunar Cartilages. B Tibia. i. — Head of the Tibia. Ic. — Malleolus Internus. C. — Fibula. 1. Head of the Fibula. m. The Malleolus Externus. D.— Bones of the Tarsus, j n. — Astragalus, j o. — Os Calcis. .< p. — Fore-part of the Tarsus. I E. — Bones of the Metatarsus. | F. — Phalanges of the Toes. PLATE III. Represents a Side View of the Male Skeleton. A- The Bones of the Cranium, B. — Bones of the Face. 1 C. — Jaws. ' D. — Clavicle. |1 E. — Os Humeri. F. — Radius, iI HG. ——. BonesUlna. of the Hand. ! I. — Ribs. I K. — Lumbar Vertebrae. , L. — Os Innominatum. M. — Os Femoris. "* N- — Patella. < O. — Tibia. P. — Fibula. ! Q. — Os Calcis. j R- — Metatarsus. .' S. — Bones of the Foot. p 3 ; PLATE IV. fig. r. Connected View of the Bones of the Head and Face. A. Os Frontis. B. Os Parietale. C. Os Temporis. D. Temporal Process of the Sphenoid Bone. E. Os Unguis. F. Os Malae. F. Ossa Nasi. G. Maxilla Superior. II. Septum Nasi. I. Spine formed by the Superior Maxillary Bones. K. The Teeth. L. Maxilla Inferior. FIG. II. A. Os Frontis. B. Os Parietale. C. Os Occipitis. X). Os Temporis. E. Temporal Process of the Sphenoid Bone. F. Os Malac. G. Maxilla Superior. H. Ossa Nasi. I. Maxilla Inferior. K. The Teeth. L. Pars plana of the Ethmoid Bone. M. Os Unguis. The particular parts of these Bones will be found in the following Plates. PLATE V. FIG. I. Is an Internal View of the Os Frontis. A. The Concave Surface of the Os Frontis. B. Internal Spine, to which the Dura Mater is fixed. C. Space between the Orbitary Processes, into which the iEthmoid Bone is fixed. D. The Serrated Edge, which helps to make the Co- ronal Suture. E. Orbitary Plate. F. F. External Angles. FIG. II. Is the External View- A. Os Frontis. B. Superciliary Foramen and Ridge. C. Muscular Print of the Right Side. D. Temporal Fossa. E. G. External and Internal Angular Process. G. Nasal Process. II. Orbitar Plate. I. Unequal Edge by which this Bone is connected with the Sphenoid. K. Points out the situation of the Lacrymal Gland- L. At this point the Cheek Bone unites. FIG. III. The Outer or Convex Part of the Parietale marked A. B. Rugged Edge, which, when joined to its fellow, makes the Sagittal Suture. C. The Anterior Edge. D. Posterior. E. Inferior Semi-circular Edge. p 4 F. Parietal Hole. G. The Arched Ridge. H. Anterior and Superior Angle. I. Anterior and Inferior Angle. K- L. Posterior Angle- FIG. IV. A. Inner Concave part of the left Os Parietale. B- Superior Edge; the indentations are more apparent here than on the Outside. C. Anterior Serrated Edge. X). Posterior Serrated Edge. E. Inferior Edge- F. Parietal Hole. G- Ramifications of the Artery of the Dura Mater. H. The Superior Angles. I. The Inferior Anterior Angle. K. A Depression which marks part of the Lateral Sinus. FIG. y. VI. Explain the Inner and Outer Surface of the Occipital Bones, The Letters and Figures apply to both- 1. The Upper Transverse Spine. 2. — Smaller and Lower Spine. 3. — Perpendicular Spine. 4. — Great Tuberosity. A. — Cuneiform Process- B. — Condyle. C- Foramen Magnum. jD. Condyloid Foramen. E. Posterior Condyloid Foramen. 5. Ridge, to which the Tentorium is fixed. 6. The two furrows, in which lie the right and left Lateral Sinuses. 8.7. Fossa Cerebelli.Cerebri. PLATE VI. 9. Internal Middle Spine, to which a Process of the Dura Matter is attached, A. Cuneiform Process. C. Foramen Magnum. D. Hole for the ninth pair of Nerves. F. The hollow in which the end of the Lateral Sinus lies. PLATE VI. FIG. 1.—II. External and Internal View of the Temporal Bone. ! The Letters not found in the one will be found in the other. {* a, a. The Squamous or Thinner Part, t b, b. The Pars Petrosum. | c. Occipital, or Mastoidean Angle, tj d. Meatus Auditorius Externus. 4 e. Meatus Auditorius Internus. .[ f. The Videan Foramen. PLATE VII. J b. The Pore End of the Spongy Bone, f ; c. The end which is turned backwards in the Nostrils. FIG. X.—XL—XII. Are Views of the Palate Bones. X—XL Show the Palate Bones, separated from each other, and from the other Bones. Fig. XII. shows them joined together, a. Palate Plate, j b. Pterygoid Process. c. Nasal Plate. d. Orbitary Processes. e. Cells of the Palate Bone. f. Broad Surface^ by which the Palate Bones are op- posed to each other. g. Point, from which the Pap hangs. PLATE VIII. FIG. L—II. Views of the Inferior Maxillary Bone. The Letters apply equally to both. i | a. The Chin. b. The Base of the Jaw extending from the Chin to the Angle. ^ 7. Angle of the Jaw. ) l. Coronoid Process. I \ Condyloid Process. 1 \ The Great Hole which receives the Lower Max- illary Nerve. \ r. Alveolar Process, s' i.h. Foramina Menti. FIG. III. A View of the InnerCranium. Surface of the Base of the 1■ i. The Os Frontis. ' The Crista Galli and Os Ethmoides. c. The Sinus Frontalis. d. The Sella Turcica. e. The fifth Foramen. g. The Processus Jugales. h. Foramen Magnum. i. The outside of the Os Occipitis. FIG. IV. Represents the Outer and Under Surface of the Skull, turned a little to the Left. a. The Parietal Bone. b. The Lambdoid Suture. c. c. The Large Transverse Arched Ridge of the Oc- cipital Bone. d. d. The Smaller Transverse Ridge, with Muscular Prints on each side of it. e. The Spinous Tuberosity, seen in some Skulls only. f. The Perpendicular Spine. g. The Foramen Magnum. /. The Cuneiform Process. *, i. The Articular or Condyloid Processes. k, k. The Posterior Condyloid Foramina. l. The Squamous Portion of the Temporal Bone. m. The Squamous Suture. n, n. The Mastoid Processes. o, o. The Mastoid Fissures. p. The Foramen Mastoideum. q. The Zygoma and Zygomatic Suture. r. The Glenoid Cavity at the root of the Zygoma, fox the Articulation of the Lower Jaw. s, s. The Styloid Processes, behind the roots of which the Foramina Stylo-mastoidea are concealed* t. The Meatus Auditorius Externus. u, u. The Foramina Carotica. v, v. The Jugular Fossae. n, tv. The Pterygoid Fossae, at the sides of which are the Pterygoid Plates. x. The Temporal Process of the Sphenoid Bone. y. The Spinous Process and Spinous Hole of that Bone. z. z. The Osseous Mouths of the Eustachian Tubes. -fv* PLATE VIII. 1, L The Foramina Ovalia. 2, 2. Passages common to the Occipital, Temporal, and Sphenoid Bones. 3,3. The Foramina Pterygoidea. 4. The Inferior Orbitar Fissure. 5. The under part of the Tuber, or Bulge of the Su- perior Maxillary Bone. 16, 6. The inner sides of the Ossa Malarum. |7,7- aThe view Superior of the back and partInferior of the Spongy Nostrils. Bones, with 8. The Posterior Edge of the Vomer. , 9,9. The Palate Plates of the Superior Maxillary Bones, with the Longitudinal Palate Suture. | 10,10. The Palate Plates of the Palate Bones, with the Transverse, and Continuation of the Longi- tudinal Palate Sutures. ill, 11. 1'he Foramina Gustativa, or Posterior Palate Holes. 912. The Foramen Incisivum, or Anterior Palate Hole. |jl3,13. The Teeth, divided into two Incisores, two small Molares, and three large Molares on each side. PLATE IX. FIG. I. Us a Draining of the Atlas, where that part, called the Body in the other Vertebra, is wanting, and the place of the Body supplied by-Articulating Sur- faces. \ Fig. II. Is the Dentata, and Fig: III. is the Atlas and Dentata connected. Fig. I.-II.- III. Are explained by the following letters. j a. Body of the Vertebra. 1 b. Articulating Surfaces. c. Spinous Processes. , d. Transverse Process. e. The Tooth-like Process. it Fig. IV. Shows the Character of the Cervical Verte- bra ; and is explained as in the former Figures. PLATE IX. Fig. V- VI. Shew the Manner in which one Dorsal Vertebra sits down on another; d% in Fig. V. is the End of the Rib in its proper place. The other Letters are explained as in the former Figures. Fig. VII. Shows the Character of the Lumbar Verte- brae, and in this Drawing the Osseous Ring marked F. is seen. The. other fetters as in former Fi- gures. FIG. VIII. Shows the whole Length of the Sternum. . A. Its Upper Part. B. Second Part. c. Ensiform Cartilage. d. Articulating Surfaces. FIG. IX.—X. Are Drawings of the Ribs. a. Marks the Head of the Rib- b. The Neck. c. The Tubercle, by which it is articulated with the Transverse Process. d- Another Tubercle. e. The Angle. f. The Groove. g. The Spongy End of the Ribs. PLATE X. A View of the whole Bones of the Trunk. A. The Ring of the Atlas. B. The Top of the Tooth-like process of the Denta- tus. C. The Bodies of the Cervical Vertebrae D. Their Transverse Processes. E. The Holes betwixt the Vertebrae, by which the Cervical Nerves come out. F. The First Rib. G. G. The Seven True ribs. a, a. Marks the end of the Ribs which receive the Cartilages. PLATE X. H. The Three False Ribs, whose Cartilages run into the Cartilages of the Seventh Rib. I. The Two Ribs, whose Cartilages are not attached either to the other Ribs or the Sternum. The Cartilages of the Ribs. The First Piece of the Sternum. The Second Piece of the Sternum. The Ensiform Cartilage. The Clavicle. Lower Part of the Scapula. b. Its Acromion Process, c. the Glenoid Cavity* d. The Coracoid Process. Q. Bodies of the Lumbar Vertebrae. R. The Transverse Processes of the Lumbar Vertebrae. e, e, e- Marks the Intervertebral Substance. S. The Os Sacrum. f, f. Marks the Holes of the Sacrum. g, g. The different pieces of which the Sacrum is com- posed. h. The Sacro Iliac Symphisis. T. Os Ilium. i. Ala Ilii. k. Spine or Ridge of the Ilium. l. Spinous Process. m. Inferior Spinous Process. n. Dorsum Ilii. V, U. Marks the Ischium. o. Its Body. p. Its Spinous Process. q. Tuberosity. r. Ramus or Branch. V. Marks the Pubis. s. The Body where it forms part of the Acetabulum. t. Crista Pubis. u. SymphisisT '•Pubis. ’5 Pubis. y. Acetabulum. •4 PLATE XL FIG. I. The Fore Side of the Os Femoris. A. The Head of the Gs Femoris. B. The Neck of the Os Femoris. C. The Great Trochanter. D. The Little Trochanter. .E, F. The Two Lower Apophyses of the Os Femoris. G. That part of the Os Femoris upon which the Pa- tella lies. FIG. II. The Back Side of the Os Femoris. A. The Head of the Os Femoris. B. The Great Trochanter. C. The Neck of the Os Femoris. D. The Body of the Os Femoris. E. Remarkable Roughness near the Trochanter. F. The Little Trochanter. G. Linea Aspera. H. I. The Two Lower Apophyses of the Os Femoris. K, K. The Parts of the Os Femoris against which the Tibia moves. L. A Cavity between the two Apophyses. FIG. III. The Outer Side of the Patella. FIG. IV. The Under Side, or that which Moves on the Os Femoris. FIG. V.. The Fore Side of the Tibia. A. A Process from which the Cross Ligaments arise. B. The Process to which the Ligament of the Patella is fixed. C A Remarkable Impression of the Muscles. PLATE XI. D. The Process which makes the Inner Ankle. E. That end of the Tibia which articulates with the Foot. F. The Head of the Fibula. G. The end of the Fibula that makes the Outer Ankle. FIG. VI. The Back Side of the Tibia. A. That part of the Tibia with which the Head of the Fibula is articulated. B. B. The Sockets in which the Apophyses of the Os Femoris are received. C. The Process from which the Cross Ligaments arise. D. The Perforation through which the Vessels pass to the Internal Substance PLATE XXX. f. The Neck of the Scapula. . The Spine of the Scapula i. The Acromion Process. k. The Coracoid Process. I, l. Marks the Outer Surface. m, m. Marks the Inner Surface. FIG. IV. This Drawing will give an idea of the Situation of the Bones oj the Carpus, and the Bones of the Hand. a. Is the Scaphoid Bone- b. The Lunar Bone. c. The Os Cuneiforme, behind which is d. The Os Pisiforme. e. The Trapezium, which supports the Thumb. f, g, h. The Trapezoides, Magnum, and Cuneiforme, supporting the fingers- FIG. V.—VI. Are Drawings of the Os Humeri. The Letters run through both Figures. a. The Head. b- The Neck. | c. The Greater Tuberosity. d- The Lesser Tuberosity. e. The Groove. \f. A Ridge on the Inner Side. I g. Is another Ridge on the Inner Side, each running to its own Condyle. I h- Is the External Condyle. | i. The Inner Condyle. 11 k. The Articulating Surface to which the Ulna is join- ed. 1. Small Round Knob. 1. The Hole which receives the Coronoid Process of the Ulna. m. The Hole which receives the Olecranon. N IPLATE XI IT. FIG. VIL Explains the Ulna. a. The Great Sigmoid Cavity. b. The Olecranon. c. The Coronoid Process. d- The Lesser Sigmoid Cavity. e. A Prominent Rough Surface, into which the Head of the Brachius Internus is inserted. f. The Ridge from which the Interosseus Membrane arises. f. The Lower Head of the Ulna. ■ The Styloid Process of the Ulna. FIG. VIII. The Radius and Ulna joined together. The Letters on the Ulna are the same as FIG. VII. Those of the Radius are, a. a. a. Show the Triangular Form of the Bone. b. The Upper Head of the Radius. c. The Neck of the Radius. d- The Tubercle into which the Tendon of the Biceps Muscle is inserted. e. The Lower Head of the Radius. f. The Scaphoid Cavity. g. The Styloid Process of the Radius. PLATE XIII. This Plate gives a Complete View of all the Bones of the Pelvis, separately and connected. FIG. I.—II. Are Views of the Os Sacrum. Fig. I- II. are explained by the same Letters. a. The Superior Surface of the Os Sacrum. b. The Osseous Ring which surrounds this Surface. - 4 ) dtU{T) arc Yt)Lc/„ ove is made by the tendon of the flexor pollicis lon- ; and from the thin protuberance on this internal *, the cartilaginous ligament that supports the as~ galas, goes out to the os naviculare ; on which liga- nt, and on the edge of this bone to which it is fixed, groove is formed for the tendon of the ^eaor digi- m profundus. he lower surface of this bone is pressed flat at the k part, by the weight of our bodies; and immediately >re this plane, there are two tubercles, from the in- lal of which the musculus abductor pollicis, flexor Itorum sublimis, as also part of the aponeurosis plan* Os calcis, crrtfwt, calcar pedis. Fibular.Flexores digitorumE. accessorii. E. X Tibial. E 214 OF THE SKELETON. taris, and of the abductor minimi digHi, have their on gin ; and the other part of the abductor minimi dipM and aponeurosis plantaris rises from the external. Bfl fore these protuberances this bone is concave, for lodgl ing the flexor muscles ; and at its fore-part we ma| observe a rough depression, from which, and a tubetf cle behind it, the ligament goes out that prevents tn bone from being separated from the os cuboides. The fore-part* of the os calcis is formed into an b [ long pulley-like smooth surface, which is circular its upper external end, but is pointed below. Tt smooth surface is fitted to the os cuboides. Though the surfaces, by which the astragalus a| ‘ os calcis are articulated, seem fit enough for motion yet the very strong ligaments by which these bonjj * are connected, prevent it, and render this principi ’ part of our base, which rests on the ground, to wi the os calcis, firm. Birth.State at dinaryA large time share of birth, of the and heel-bone the large is knob ossified appears at the aft*