The A to Z of Bones of The Skull Dr A. L. Neill BSc MSc MBBS PhD FACBS [email protected] For Stable Angina Pectoris Pizotifen malate Indications: Prophylactic treatment of vascular headaches including typical and atypical migraine; vasomotor and cluster headaches. The A to Z of Bones of The Skull The A to Z of the Bones of the Skull Introduction After the A to Z of Skeletal Muscles was released to my students (and later my colleagues with the help of Aspen), I received some very valuable feedback from both. From this feedback it became apparent that this format was helpful to all in the health professional field. It was also apparent that there was a need for another pocket reference book of this type on bones and nerves. So as with the other book, I have started with a prototype examining the bones of one of the most complex group in the body, the SKULL. It is hoped that this proves to be as useful as my first A to Z book, and goes on to become a more comprehensive but quick and simple reference for all bones. Acknowledgement I would like to thank Aspen Pharmacare Australia and particularly Mr Greg Lam CEO and Mr Robert Koster Head of Marketing and Sales for stepping in and giving me their support in this project when it seemed I was not going to be able to complete it, due to lack of resources and time. Students, as always, but particularly today have to sacrifice many things in their pursuit of knowledge. It is hoped that this book will help to make that pathway easier and more enjoyable. As with my other ventures in this A to Z series we want to give knowledge to any who wish to use it. Dedication To MICKEY 390335, and to stopping pettiness, spite and misinformation wherever it lies. 1 © A. L. Neill The A to Z of the Bones of the Skull How to use this book After examining the SKULL as a WHOLE from many view points, identifying individual bones, cavities, impressions and surfaces and including common radiological views, with explanatory diagrams, this book lists all the bones of the skull in ALPHABETICAL order as far as possible. Images of the Skull “in situ” are also included. Features are named using in the most familiar terms and those agreed upon by anatomical nomenclature convention avoiding eponymous terms wherever possible but as with all anatomical studies sometimes several terms are used to name the same feature. Wherever this is common and to save confusion reference is made to each term. Similarly between disciplines such as radiology and osteology as well as anatomy the same view may be described several different ways, so when this is also common and to provide clarity these terms are mentioned. The pages facing each image contain the key/legends to the labels on that diagram. This is to help in the learning of the features and to prevent confusion in the examination of the bones. Numbering commences anew with each diagram. However, with some bones one view is not enough (e.g. Temporal and Sphenoid) to conceptualize all the surfaces and articulations, so these bones are then shown with the same numbering sequentially in an alphabetical way, on each related diagram. Occasionally they are also shown “in situ”, in other words as they lay in the skull. This is particularly the case with the Palatine bones. These bones are hard to see as they are surrounded by other structures and deeply embedded in the head, so several views and rotations of the bone are shown and labelled to see their connections, as well as a view showing how they are placed relative to other bones. © A. L. Neill 2 The A to Z of the Bones of the Skull Capitalization is used to demonstrate the bones involved in several structures including joints of all kinds (e.g. sutures). In other words the parietomastoid suture is listed as Parieto- Mastoid suture to further remind the reader of the involved bones or bony features involved in the composition of the structure. This helps to further orientate the reader to the structural components of the feature. It is hoped that this will prove a valuable resource for those examining individual bones as in the study of ANATOMY and its many uses such as: archeology, anthropology, chiropractic dentistry, forensics, geology, medicine, orthopaedics, osteology, paleontology, paleobiology, physiotherapy and surgery. It is to be a forerunner of a more complete listing of all bones from A to Z and a more extensive development of other aspects of the skull such as measurement markers, development milestones, individual and ethnic variations - “the A to Z of the Skull part II”. Hence any suggestions on format or inclusions will be gratefully received. Thank you Amanda Neill BSc MSc MBBS PhD FACBS ISBN 1 74138 166 5 3 © A. L. Neill The A to Z of the Bones of the Skull articulates at the Redonly spots synovial indicatejoint inwhen the skull- therethe is TMJ an - articulationtemporomandibu or jointlar betwee joint. Alln the bones.other Please joints are notesecondary the hyoid doescartilagenous not articulatebone- with anyfibrocartilage bones and - the mandible bone. © A. L. Neill 4 The A to Z of the Bones of the Skull Table of contents Introduction 1 Acknowledgement 1 Dedication 1 How to Use this book 2 Table of Articulations of the Skull 4 Common Terms used in Osteology 7 Classification and summary of skull bones 12 The Skull 13-36 External Skull Anterior (norma frontalis) radiology - occipitofrontal (complete) radiology - occipitofrontal (upper aspect) radiology - occipitomental (lower aspect) External Skull Inferior (Base of Skull) (norma basilaris) radiology - submentovertical view (view from below) External Skull Lateral (norma lateralis) radiology - lateral External Skull Posterior (norma occipitalis) External Skull Superior (norma verticularis) Internal Skull Inferior - Skull Cap Internal Skull Superior - Internal Base - cranial fossae Bones of the Skull 37-70 Auditory Ossicles: malleus, incus and stapes enclosed within the Temporal bone Ethmoid bones Anterior & Lateral, Superior, Medial Frontal bone Hyoid bone Lacrimal bones Mandible radiology - Orthopantomogram = OPG (Anterior) radiology - Lateral (with soft tissue) radiology mandibular joint (jaw) open and closed see also TMJ (temporomandibular joint) Maxilla / Maxillae bones Maxillae bones Inferior 5 © A. L. Neill The A to Z of the Bones of the Skull Nasal bones Occipital External, Internal Palatine bones Parietal External, Internal Sphenoid Anterior, Posterior Sutural / Extrasutural bones - Incus Temporal External, Inferior, Interior Vomer Zygoma Cavities of the Skull 71-90 Anterior Cranial Fossa Base of the Skull internal Cranial Fossae Anterior, Middle, Posterior Maxillary Sinus Middle Cranial Fossa Nasal cavity Dissected, Lateral, Septum Orbital cavity (Orbital fossa) Anterior radiology obital cavity anterior radiology orbital cavity lateral Posterior Cranial Fossa © A. L. Neill 6 The A to Z of the Bones of the Skull Common terms in Osteology (the study of bones) (with particular reference to the skull) Ala A wing, hence a wing-like process as in the Ethmoid bone pl.- alae. Alveolus Air filled bone - tooth socket Aperture An opening or space between bones or within a bone. Areola Small, open spaces as in the areolar part of the Maxilla. Articulation Joint, which is a point of contact b/n 2 opposing bones. Auditory Pertaining to hearing, hence, pertaining to the ear. Axial Refers to the head and trunk (vertebrae, ribs and sternum) of the body. Basilar Relating to the base or bottom of structures Basiocranium Bones of the base of the skull Boss A smooth round broad eminence - mainly in the Frontal bone female > male Bregma Refers to a junction of more than 2 bones in a joint as in the Bregma of the skull, junction between the coronal and sagittal sutures which in the infant is not closed and can be felt pulsating - site of the anterior fontanelle. Calotte The calotte consists of the calvaria from which the base has been removed. Calvaria The calvaria refers to the cranium without the facial bones attached. Canal Tunnel / extended foramen as in the carotid canal at the base of the skull adj,- canular (canicular - small canal) Caput / Kaput The head or of a head, adj.- capitate = having a head (c.f.decapitate) Carotid To put to sleep; compression of the common or internal carotid artery causes coma. This refers to bony points related to the Carotid vessels Cavity An open area or sinus within a bone or formed by two or more bones (adj. cavernous), may be used interchangeably with fossa. Cavity tends to be more enclosed fossa a shallower bowl like space (Orbital fossa-Orbital cavity). Cavum A cave. Cephalic Pertaining to the head Clinoid Like a bed-post, part of a four poster bed so that clinoid process looks like a bed post (generally with other posts) as in the Sphenoid bone. Clivus A slope hence in the anterior cranial fossa referring to a slope on the base of the cavity. Cochlea A snail hence snail-like shape relating to the Organ of Corti in the ear. Concha A shell shaped bone as in the ear or nose (pl. conchae adj. chonchoid) old term for this turbinate. Condyle A rounded enlargement or process possessing an articulating surface. 7 © A. L. Neill The A to Z of the Bones of the Skull Cornu A horn (as in the Hyoid) Corona A crown. adj.- coronary, coronoid or coronal; hence a coronal plane is parallel to the main arch of a crown which passes from ear to ear (c.f. coronal suture). Cranium The cranium of the skull comprises all of the bones of the skull except for the mandible.