THE MAIN PERIPHERAL CONNECTIONS OF THE HUMAN SYMPATHETIC NERVOUS SYSTEM By T. K. POTTS, M.B., CH.M. (SYDNEY)1 BIIE recent investigation (5,7) of the functional significance of the sympathetic system by 1)r N. D). itoyle and Professor J. I. Hunter has revealed the necessity for a re-examination of the anatomy of the human sympathetic system. Ini particular the operations of ramisectioni (7, 8) devised by Dr Royle, in collabora- tion with Professor Hunter, call for a more exact determination of the precise position and topographical relations of the sympathetic cord and its ram? cotitnunicantes than at present is available. The dissection described ill this note was undertaken primarily to provide the surgeon with this guidance. In this matter, two regions stand out as having assumed an added interest ill the light of recent research. I refer to those regions associated with the operations known as cervical, and lumbar sympathetic ramisection, which are performed to remove the rigidity of the musculature of the extremities ill spastic paralysis (2,3,4,5, 7, 8, 9,10). As a description of the rari commnunicantes necessarily involves some mention of the arrangement of corresponding ganglia, this will be done in considering the various regions. To facilitate demonstration, the services of Miss D. Harrison were procured and, under my guidance, faithful repro- dluetions of the dissection were made by her. The dissection has been mounted, and placed in the Wilson. Museum of Anatomy, at the Medical School, Uni- versity of Sydney. The cervical portion of the sympathetic is characterized by the absence of segmental ganglia, and of white rami comnimunicantes. Two constant ganglia are found-the superior and inferior -and a variable middle cervical , variable in that it may be absent; and, whehn present in its usual position, lying commonly about the levelof the inferior thyroid , i.e. the level of the 6th cervical ; or else lying in close proximity to the inferior cervical ganglion. When this latter arrangement is found, the two ganglia are commonly united by stout cords embracing the . The absence, or the position when present, of this middle ganglion, affects the arrangement of the grey rami to the 5th and 6th; or 4th, 5th, 6th and 7th cervical . The superior cervical ganglion is usually placed at the level of the 2nd and 3rd , and under cover of the posterior belly of the , or a little above that level. This ganglioni furnishes grey rami to the 1st, 2nid and 3rd, and, sometimes also, the 4th cervical nerves; in this specimen. 1 From the Department of Anatomy, University of Sydney. Anatomy LIX '3 130 T. K. Potts to the 1st, 2nd and 3rd only. The 1st cervical is not shown in the diagram (vide Pls. 1 and 6). These rami lie in the region of the lateral border of the longus eapitis muscle, and join the nerve, as a rule, as it lies in the groove of the transverse process of the vertebra, or as it emerges from the groove be- tweeni the anterior and posterior tubercles of the transverse processes. Further- iiore, the ramus joins the nerve on the anterior, or antero-iinferior aspect of the nerve. I have not seen an instance of a ramus junctioning with a on the posterior aspect of the latter. The middle cervical ganglion, when situated about the level of the 6th cervical vertebra, usually supplies rami to the 5th and 6th cervical nerves; at times, also, to the 4th and 7th. When this ganglion is absent, or lies in close proximity to the inferior cervical ganglion, these cervical nerves, the 5th and 6th, and possibly also the 4th and 7th, usually derive their rami direct from the (PI. 1); and it is my experience that this middle ganglion, when lying adjacent to the inferior ganglion, plays a subsidiary role from the point of view of furnishing rami to the cervical nerves. In this specimen only one ramus, viz. one to the 8th nerve on the right side, arose from this ganglion; but the ganglion contributes largely to the cardiac plexuses -especially on the left side (PI. 1). Here I would draw attention to two rami (PI. 1) arising from the symi- 1athetic trunk about the level of the anterior tubercle of the transverse process of the 6th cervical vertebra. They run a more or less parallel course, cranially and medially, pierce the longus colli muscle, and then pass directly backwards in the interval between the transverse processes of two adjacent vertebrae; and, in this case, the upper ramus is associated with the 5th cervical nerve, and the lower with the 6th. Both these rami effect junction with the nerves as the latter lie in the grooves of the transverse processes of corresponding vertebrae. At first I thought these rami were muscular twigs to the longus colli muscle; but subsequent dissection revealed the facts as stated. In addi- tion, both rami give twigs to the vertebral artery. The inferior cervical ganglion is commonly situated in the region of the level of the of the first rib, but may occupy a slightly lower level. The ganglion supplies rami to the 7th and 8th cervical, and ist thoracic nerves (Pls. 2 and 7). A single ganglion may supply two or more spinal nerves, or two ganglia may supply a single spinal nerve; and here is an excellent illustration of the former. A rams ascends in front of a spinal nerve, or nerves, if that ramus is associated with a nerve at a higher level. For example, it passes in front of the 8th and 7th if ascending to the 6th cervical nerve, and does not pass behind the nerve or nerves. A ramus in this region measures, as a rule, from *5 mm. to 1*5 mm. across. The scalenus anterior mnusclc presents an important relation to the grey rami in this region. The 5th and 6th or 7th nerves may lie in front of this muscle, may pierce the niuscle, or may lie under cover of the ninscle. So that in some cases iii which these nerves lie upon, or pierce this muscle, it is not Connections of thef Sympathetic 131 tlncomnl1oln to find all the ramii, or sonic of theni, lying upon the surface of the muscle, or wandering among its fibres. In the supposedly normal type, when these cerv-ical nerves lie behind the muscle, the rami may lie upon, or pierce the muscle. The inferior cervical ganglion is here shown as supplying one grey ranmus to the 6th cervical nerve, two to the 7th, three to the 8th, and one to the 1st thoracic nerve, i.e. seven. There are still others requiring mention. I wish to draw attention to two or three rami on this specimen which lie to the medial side of the vertebral artery in a triangle formed by the upper border of the neck of the first rib below, by the lateral margin of the longus colli muscle mcdially, and by the medial border of the vertebral artery laterally. The shorter and more medially placed is a large ramus (which may be double) lying almost under cover of the lateral border of the longus colli muscle (PIs. 1, 2 and 7). It joins the 8th cervical nerve under cover of the muscle. The other rams, single on the left side, double on the right, lies to the outer side of the last-mentioned ramus; and, taking the medial border of the vertebral artery as its guide, ascends upwards, and medially. This ramus appears to be fairly constant. It was present in the same position as a single trunk on the left side, and as a double trunk on the right in this specimen; and as a single trunk it was present on both sides of a full-term foetus; and also in a dissection of another adult cadaver. On only one occasion was it a double trunk. In every instance its main association is with the 7th cervical nerve; the greater pro- portioll of its fibres turningldistally at its point of junction with the nerve, while the nerve lies in the groove between the 6th and 7th cervical vertebrae. A fine branch is also continued upwards to the 6th cervical nerve; and in one case was followed on to the 5th nerve. At first I regarded this rams as the vertebral plexus, aggregated into a single or double trunk at its commence- ment; but subsequent dissection has convinced me that it is a grey rams associated mainly with the 7th cervical nerve. To sunmmarisc, then, I have found three rami to the 5th cervical nerve; three to the 6th; three to the 7th, and three to the 8th; so these cervical nerves, 5th, 6th, 7th and 8th, may derive their rami from three sources, viz. from the sympathetic trunk; from the middle cervical ganglion (whatever its position when present); from the inferior cervical ganglion. In addition to these, Spalteholzli) mentions branches from the vertebral plexus to these cervical nerves. The first white rams, which is associated with the 1st thoracic nerve, connects this nerve to the inferior cervical ganglion, or to the 1st or 2nd thoracic ganglion. This white rams is larger and whiter than the corre- sponding grey ramnus, and lies lateral to, or lateral and posterior to the grey ramus, and is directed from above downwards and medially (Pls. 6 and 7). This white ramnus must be left intact in the operation of cervical ramisection if papillary effects are to be avoided. The thoracic region is characterized by the segmental arrangement of ganglia; and, further, by the fact that there is at least one white and one 132 T. K. Potts gYrey l',lmms associated wN'ithl each thoracic jierve (Pis. 3 and 6). These white ramni, together with those of the I st and 2nid, or :3rd lumnbar nerves, constitute the thoraco-lumnbar outflow; which is restricte(l to that portion of the cord which lies between the cervical and himlbar enlargements. These latter, to (qluote Langdon Brown (6), "are devoted to the innervation of somatic muscles of the limbs. So much have these areas become specialised for this purpose, that the limbs have to obtain their visceral fibres from the part of the cord which lies between them." Ini the thoracic segments the white ranius is more caudally placed than the accompanying grey ran-is. Here again coalescence or fusion of neigh- bouring ganglia will somewhat affect the point of attachment of rami to the ganglia or sympathetic trunk. The general direction of the white ranmi in the is from above, downwards, forwards and medially; and of the grey, upwards, backwards and laterally, with the exception of those grey rami of the 11th and 12th nerves, which are seen to descend from above, downwards, backwards and laterally. here I may mention some of the common methods of junction of ramni with ganglia or cord on the one hand, and with spinal thoracic nerves on the other (PIs. 3 and 6). There is a single rams to the 2ind thoracic nerve. This is probably a mixed white and grey ramus. A simple arrangement is seen in the case of the 1st and 3rd nerves in which each ranms effects junction independently with both ganglion and spinal nerves. In the case of the 4th and 5th nerves, the two rami arc fused at the point of junction with the nerves, and each ramus joins the corresponding ganglion inde- peendently. The reverse of this may occur, as in the case of the 9th nerve-the rami arise independently from that nerve, and coalesce before joining the corresponding ganglion. The 7th, 8th and 10th nerves have three separate communications, and more or less complete fusion of these occurs before connection with the ganglia, or as occurs in the case of the 7th nerve, with the sympathetic trunk. The reverse of this is seen at the 11th and 12th nerves; except that, at the 12th, there are four rami instead of three, as at the 11th. It will be noticed also that the rami tend to increase in length; and the number of rami to each nerve to increase as we proceed towards the . The increase in length is due to the forward inclination of the sympathetic trunk as it approaches the lumbar region. From the 9th, 10th, and 11th and 12th nerves, some branches to the intercostal niuscles are given off, which at the 1oth, and to a lesser degree at the 9th, are closely associated with the rami. The most caudal ramus of the 12th nerve joins the sympathetic trunk behind the renal artery. The next rannis above joins the nerve to the last thoracic ganglion; and the two ascending rami join the nerve to the last ganglion buit one, thus affording an illustration of two ganglia supplying a single nerve. The abdominal part of the sympathetic trunk (Pls. 4, 6 and 8) lies uiponi the bodies of the vertebrae, along the medial border of the psoas major muscle; and on the right side it is under cover of the inferior vena cava, and usually in front of the lumbar vessels; but also may lie behind. On the left side the Connections of the Sympathetic 133 trunk usually lies in front of the vessels. The number of ganglia in the lumbar regions is very variable. "The ganglia are small; commonly four are, but a smaller number may be present. There are usually two connecting branches to each ganglion(12)." llarman(l) states that "the segmental arrangement of ganglia is the exception in this region, numbering up to eight"; and further states that "the numerical arrangement of the rami was even more variant, four rami to a ganglion being common." Ile also reports the double nature of the cord in this region. This condition existed on both sides in this specimen. Harman also states that " there is a marked and sudden change in the character in the constituents of the rami in connection with the 2nd and 3rd lumbar nerves. The rami of the 2nd nerve contain many fine medullated fibres, and which are arranged in characteristic bundles which number on an average over two hundred fibres, whilst the ramus of the 3rd nerve contains but few medullated fibres; and these are of quite a different character, and scattered at intervals throughout the mass of the non-medullated fibres in a manner which distinguishes them from the typical bundles of small, white. efferent fibres of a white ramus. The presence of a few scattered white fibres in a ramus otherwise grey does not constitute that ramus a white ramss" The rami pass under cover of the fibrous arches which give origin to fibres of the psoas major muscle; but in some instances may traverse the fleshy origin of this muscle; and in Quain's Anatomty it is stated(l12) that "the rami may pass superficial to these fibrous arches." Four ganglia are present in this specimen on both sides. The uppermost is a large ganglion lying upon the lower half of the body of the 2nid lumbar vertebra, the inter-vertel)ral disc, and the upper half of the body of the 3rd1 lumbar vertebrae. The 2nd and 3rd ganglia are almost fused, a slight coni- striction differentiating them. From this level to the 4th lumbar ganglion the cord is double, although on the left side the posterior division may be regarded as a rams to the 5th lumbar nerve, communicating by a fine thread with the 4th lumbar ganglion. On the right side, the two divisions reunite, and are continued downwards as the main-trunk. The rami of the five lumbar nerves number two in each case. An elongated grey rams descends from the last thoracic ganglion to the first lumbar nerve. From this nerve a large white ramus descends downwards, forwards and medially to join the uppermost lumbar ganglion in this case, or the 2nd ganglion when that exists indepen- dently. This is a very constant ramus, and can be readily avoided in lumbar ramisection. Some of its fibres are ultimately distributed to the bladder and rectum by way of the hypogastric nerves. The rami of the 2nd lumbar nerve pursue an arched course from the ganglion, upwards and backwards, and then turn abruptly downwards and backwva1ds to join the nerve. The rami of the 3rd lumbar nerve proceed from the lower end of the uppermost ganglion down wards and backwards. Neither the 2nid or 3rd ganglion furnishes any ranmi directly ill this case; the rami of the 4th lumbar nerve arise from the con- striction between the two ganglia by a single trunk, and they are united before 134 T. K. Potts entering the nerve by a fine cross-branch. One rams to the 5th nerve arises directly from the 4th lumbar ganglion. The other ramus is really the con- tinuation of the larger and posterior division of the sympathetic trunk, which receives a fine communication from the 4th lumbar ganglion, as already stated. One feature of the rami of this region is that they lie in the grooves of the bodies of the corresponding vertebrae; and in general are not in contact with the prominences of the intervertebral discs. In the sacral region (Pls. 5 and 6) the sympathetic trunk is well defined; and again shows evidence of division into two strands as between the 21nd and 3rd sacral nerves of both sides, or even into three strands, as between the 3rd and 4th nerves on the left side. The ganglia in this region are very definite, are rounded, about the size of a pea, or smaller, and number four on the left side, and five on the right. The upper one or two are situated well above the corresponding nerves; but the lower two or three lie on the same level, and in close proximity to the nerves. The largest ganglion of this series is the uppermost on the right side; and in addition to supplying four rami to the 1st sacral nerve, it communicates with the 2nd sacral nerve by a large ramus, which has a definite ganglion at its junction with the nerve. This ramus also has a cross-branch connecting it with the sympathetic trunk. The 4th sacral ganglion on the left side is joined by a rams to the ganglion of the 3rd nerve of the right side, and by a second ramus to a branch from the ganglion of the 4th sacral nerve of the right side. The rami vary greatly in number; from one or two to a single nerve, up to eleven, as in the case of the 4th ganglion of the left side. On both sides there is a rich supply of rami associated with the 1st sacral nerve. On the right side, four large individual rami; and on the left, two, one of which is as large as to suggest fusion of two or more rami. Rami to the 2nd and 3rd sacral nerves pierce the pyriformis muscle. A portion of this muscle has been removed on the right side. From the ganglion of the 4th nerves of both sides, and also from that of the 3rd nerve of the right side, branches arc given off to the pelvic plexuses. One branch from the ganglion of the 4th nerve of the left side communicates with the pudendal nerve of the same side. The sacral visceral nerves, or the pelvic of Gaskell, which constitute the sacral portion of the para- sympathetic nervous system arise as usually described, from the 2nd and 3rd spinal nerves. I wish to express my gratitude to Professor Hunter for advice and infor- mation willingly given at all times. The expenses incurred in the production of this paper have been defrayed from the fund generously donated to the Anatomy Department, University of Sydney, by Geo. H. Bosch, Esq., Sydniey. Journal of Anatomy, Vol. LIX, Part 2le Plate I

/..- N Mandibulanrls M Levator. veli palatini -/ Hint carotid art A n L ru mr

Alveolar process

Muscular branches to Longus capitis Branch to Vagus I V_ Soft palaLe ToM nLgue ou VI M Longus capifit H Post. wall of lion Pha rynx '-S Sympathetic trunK -Cerv B N

Rarnus tno V. N Cerv V. N

Cerr-\vI. N Scalenus medius M. LonqLJs coCI i-

Goryv VlIl.N Middle cerv. garghioa- Inferior cerv ganglioH- Thoracic I. N- .Rib f. Cardiac branch-- .Rib 2. 3 r"Al SU

POTTS-HUMAN SYMPATHETIC NERVOUS SYSTEM Journal of Anatonty, Vol. LIX, Part 2 Plate 1I

Sympathetic trunk Ramus toV N. Ramus to . N. I Ramus to XI.N. Phrenic nerve \\ \ \ CervicaI V N. \ Mlusculus I- IIM longus Mus. scalenus medius -Capi is, Carotid tubercle Ramus toWN. vWI. ner ve Middle cervical- it_

Ri b 1. -Art. ver te s Mu's. omohyoid'eus }Rami tovvL LiL'l- Ramus toVNMN-l\_ A VII. nerves Art. vertebralis -aus toVl NW. M\us. sc a~lenus anterior -=m - nf. cerv. gang. Clavicle.-.....7 t3 Y~ ---tl t thoracic N. --Cardiac branch subcLaviusri Subctavian artery Thy reo- cerv. trunk Rib 2. Axi[lary artC"- -~v~Ant. lig. Rib 2./ Lonlgit. Rib1l./-- 1St thoracic gang. Int.mamilLaryx artery 2 ; _ Ansa ,C - u 'Cardiac branch intercostal Ii. nerve

IntercostaRl 11I.nerve R 3

POTTS-HUMAN SYMPATHETIC NERVOUS SYSTEM Journal of Anatomy, Vol. LIX, Part 2 Plate III

Thor. ver- I3. -- a M A

PUIf mcr i r y hr-(anc h

Ant. Iong. ig. -

Splanchncic gany.

Diaph rag r \ --Ext. intercos. _ _ ~m uscle Branch to intercos. Great muscle NerveSplanchnic.- Branch to Great - Splanchnic N. f l esser Sphri -.hnic- Ne rve Aorta~ :; -Int. intercosmuscie Thoracic vertl2. Sym. trunk- -Rib 12. Thoraccic XH N.

POTTS-HUMAN SYMPATHETIC NERVOUS SYSTEM Journal of Anatomy, Vol. LIX, Part 2 Plate I V of diaphragm Great splanchnic NINCrus ThoracjcX N Aorta

Rib 10-

Suprarenal gland Branches to --Adrenal gland Coeliac gang Iion- Coeliac ganglion _Adrenal branch F~1j~ epatic art Crus of diaphragm- Sympathetic ZAdrenal branch trunk SW-Sup. mes. art Renal branch- -Renal art. Renal vein- Aortico- renal gland Sympathetic trunk Kidney- Aorta Branch of aortic -- plexus Renal veinf-- Crus of diaphragm 1.t Lumbar ganglion } Hypogastric nerves Ureter Lumbar vert. 3. M. Quadratus lu mborum Inf. mesenteric art. M. Psoas minor N.l1io inguinalis M. Quadratus u m borum M.Psoas major Lumbar vert.4. llio-lumbarJ ,g. Hypogastric plexus Branch to Common iliac art. N. Geni to femr --Common iliac art. M. IIiacus- N. lat. cut.-- empatheticc trunk r" of Lumbar V. N. Hypogastric plexus , " NAT Pelvic 4ASIZE 1Z plexus

POTTS-HUMAN SYMPATHETIC NERVOUS SYSTEM Journal of Anatomy, Vol. LIX, Part ? Plate V

+ NAT. s5ZE C oC Cyx 5

POTTS-HUMAN SYMPATHETIC NERVOUS SYSTEM Journal of Anatomy, Vol. LIX, Part 2 Plate VI

46'

POTTPS-tHUMAN SYMPATHETIC NERVOUS SYSTEM Journal of Anatomy, Vol. LIX, Part 2 Plate VII

M. Longus colli Sympathetic trunk Muscular br. to M.Long.colli Carobcd tubercle

Ramusof{VIN}. \ Ramus of 1IV.N. lAM N [ Cervi~~~~~~Cev'ca Ramus of cerv.V CINrv

Branch from middle to inferior rvical VIl.N. gang. 4IScalenus med. _ Ramus of cervical Viii N.

Middle cerv. gang Rib I Cervical VEIN. Inf. cerv. gang, Suprascapular N. Grey ramus of thor.I N Branch from middle h rThoracic IN to inferior gang.- Rub 2. White ramus of Tofr.l.N. thoracic I N. J Ansa siubclaviac. Rib 4. Ramus (single) ; Rib 3. of thoracic II -N M. Longus colis Rib 2. Ant. long. lig. j;_hor. m N Cardiac branches G a ri~~~Gag ofm N _ X _ ~~~~Rib4. Recurrent laryngeal N_ a ...... f:. r~~~w L ~Rib3.

POTTS-HuMAN SYMPATHETIC NERVOUS SYSTEM Journal of Anatomy, Vol. LIX, Part,? Plate VIII Great splanchnic N. Lesser splanchnic N Renal art. Thor-acc vert. 12 Last Lhoracic gang. Sympathetic trunk AorIaAnrta r \ 1// / / ~~Rib 12 Left gastric art Left cxliac gang Art, Iienalis -Thoracic Xl N. R.ccel. gang. branches Hlepatic art._i AortLico-renal gang. Sup. mes. adrt. <;White ramus I from lumbar I. N. L. Crus of diaphragm Br. of aortic plexub

l wilubar gang I -M. Quad. lumbar Aor ta- 1/1 -Rami of lumbar II N. Aortic plexLus- A;Jbfwm -Lumbar II. N. olMo..l 1 Lumbar vert 3 -Rami of Lumbar Il N.

Inf mes art- LumbarIJ[lN.

-4 Lumbar gdI *:f, Illo-lumbar lig. Lumbar vert. r Lumbar lV. N. Rami of Lumbar IV.N. Hypogastric plexus

Common iliac art - Sympathetic trunk post. divi'sori Div. of hypogasL plex -M. Iliacus

Lumbar gang. -- N. Left pelvic plexus -LumbarV. 5 NAT. SIZE

POTTS-HUMAN SYMPATHETIC NERVOUS SYSTEM Connections of the Sympathetic 135

DESCRIPTION OF PLATES Plate I. Lateral view of the left cervical sympathetic trunk and its connections. The superior cervical ganglion has been displaced forwards slightly (I nat. size). Plate II. Front view of the lower cervical and upper thoracic region showing the sympathetic trunk and its connections (nat. size). Plate III. Lateral view of the left thoracic sympathetic trunk below the level of the fourth rib (i nat. size). Plate IV. Lateral view of the right lumbar sympathetic trunk. The vena cava inferior has been removed (J nat. size). Plate V. Front view of the sacral portion of the sympathetic nervous system (4 nat. size). Plate VI. Lateral view of the left sympathetic trunk and its connections (> nat. size). Plate VII. Antero-lateral view of the lower cervical and upper thoracic portions of the sym- pathetic nervous system on the left side to explain the structures shown in Plate VI in this region. The musculusscalenus8 anterior has been removed (nat. size). Plate VIII. Lateral view of the left lumbar sympathetic trunk to explain the structures shown in Plate VI in this region. The musculus psoas major has been removed (I nat. size).

REFERENCES (1) HARMAN, N. B. "The Caudal Limit of the Lumbar Visceral Efferent Nerves in Man." Journ. of Anat. and Physiol. 1898, vol. XXXII, p. 403. (2) HUNTER, J. I. "The Postural Influence of the Sympathetic Innervation of Voluntary Muscle." Medical Journ. of Australia, Jan. 26th, 1924, p. 86. (3) " The Significance of the double Innervation of Voluntary Muscle illustrated by reference to the Maintenance of the Posture of the Wing." Ibid. June 14th, 1924, p. 581. (4) "The Postural Influence of the Sympathetic Nervous System." Brain, Aug. 1924, Vol. XLVII, Part 3, p. 261. (5) ~"The Influence of the Sympathetic Nervous System in the Genesis of the Rigidity of Striated Muscle in Spastic Paralysis." Surgery, Gynaecology and Obstetrics, Dec. 1924. (6) LANGDON BROWN, W. The Sympathetic Nervous System in Health and Disease, London, 1920. (7) ROYLE, N. D. "A New Operative Procedure in the Treatment of Spastic Paralysis and its Experimental Basis." Medical Journ. of Australia, Jan. 26th, 1924, p. 77. (8) "The Operations of Sympathetic Ramisection." Ibid. June 14th, 1924, p. 587. (9) "The Problem of Treatment in Spastic Paralysis." Brain, 1924, vol. XLVII, Part 3, p. 275. (10) "The Treatment of Spastic Paralysis. Its Experimental Basis and Clinical Results." Surgery, Oynaecology and Obstetrics, Dec. 1924. (11) SPALTEHOLZ. Hand of Human Anatomy. (12) QUAIN (Schafer and Symington). Text Book of Anatomy, 1909, vol. iII, Part ii, p. 158.