Naziha Sultan Ahmed, BVMS, MSc Scientific degree (Prof. Assis.), Department of Anatomy College of Veterinary Medicine, University of Mosul, Mosul, Iraq https://orcid.org/0000-0002-2856-8277 https://www.researchgate.net/profile/Naziha_Ahmed Practical anatomy | Second lecture | 2nd year 2019 Skull as a whole *The ventral surface of the skull: Ventral surface formed by the following bones: -Basilar part of occipital bone. -Sphenoid bone. a-Basisphenoid bone. b-Presphenoid bone. -Vomer bone. -Pterygoid bone. -Osseous hard palate: formed by: 1- Horizontal plate of palatine bone. 2- Palatine process of maxillary bone. 3- Palatine process of incisive bone. *Ventral surface consists of 3 regions: a-Cranial region. b-Choanae region. c-Palatine region. *Cranial region: extend from the foramen magnum to vomer bone and Hamulus process of pterygoid bone rostrally. 1-Foramen magnum. 2-Occipital condyle: on each side of foramen magnum. 3-Condyloid fossa. 4-Foramen of hypoglossal canal: for passing of the hypoglossal nerve and condyloid vein. 5-Jugular process (paracondylar process) of occipital bone: lateral to each occipital condyle. 6-Muscular or basilar tubercles. CouPractical anatomy | Second lecture | Prof. Assis. Naziha Sultan Ahmed Page | 1 7-Foramen lacerum: on both side of basilar part of occipital bone. 8-Tympanic bulla: on the petrous part of the temporal bone. 9-Articular tubercle: on the ventral aspect of the zygomatic arch. 10-Mandibular fossa: on the ventral aspect of the zygomatic arch caudally to articular tubercle. 11-Retroarticular process: on the ventral aspect of the zygomatic arch caudally to mandibular fossa. *Choanae region: presents the pharyngeal opening of the nasal cavity (caudal nasal opening). It is divided by vomer into 2 choanae, which bounded laterally and rostrally by pterygoid and palatine bones and caudally by vomer bone. -Hamulus process of pterygoid bone: flank the choanal region. *Palatine region: represent by osseous hard palate, occupy more than half of the length of the ventral surface. - Palatine bone consist of: 1. Horizontal plate. 2. Perpendicular plate. -Osseous hard palate: formed by: 1- Horizontal plate of palatine bone. 2- Palatine process of maxillary bone. 3- Palatine process of incisive bone. -interalveolar space: part of dental arch without alveoli. -Maxillary tuberosity: presents caudal to last alveolus. - Median palatine suture: presents on the midline of hard palate. -Minor palatine foramen (anterior palatine foramen): represent the rostral opening of the major palatine duct. -Palatine groove: presents along each side of hard palate, contain palatine vessels and nerve. It continues with the major palatine duct. -Palatine fissure: narrow interval along the lateral margins of palatine process of incisive bone. -Interincisive foramen: represents the internal opening of inter incisive canal. CouPractical anatomy | Second lecture | Prof. Assis. Naziha Sultan Ahmed Page | 2 *The nuchal (occipital) surface (Base of skull): formed by occipital bone, separate from the dorsal surface of the skull by the nuchal crest. - Rough areas for the attachment of semispinalis capitis muscles (present ventral to nuchal crest). -External occipital protuberance: for attachment of nuchal ligaments. -External occipital crest: extend from external occipital protuberance till the foramen magnum. *Mandible (lower jaw) bone: The largest and only mobile bone of the skull. It holds lower teeth. It consist of right and left halves united by mandibular symphysis. It consist of body and two vertical rami. - Body: horizontal part bearing the lower teeth. - Mental foramen: rostral opening of mandibular canal. - Ramus: vertical part of mandible. - Articular (condylar) process: smooth process articulate with mandibular fossa of temporal bone to form temporomandibular joint. - Coracoid (coronoid) process: rostrally to condylar process. -Mandibular notch. * Body: 1- Incisive part: a- Convex labial surface. b- Concave lingual surface. 2- Molar part: bearing lower premolar and molar teeth. - Intermandibular space. - Mylohyoid line: for origin of mylohyoidous muscle. - Mental foramen: represent the rostral opening of mandibular canal, where mandibuloalveolar nerve and artery pass. - Mental foramen: present at the junction of incisive part and molar part of the mandibular body laterally. CouPractical anatomy | Second lecture | Prof. Assis. Naziha Sultan Ahmed Page | 3 *Ramus: have 2 processes dorsally, the rostral one is the coracoid or coronoid process for muscle attachment and the caudal one is called the condylar process which articulate with the mandibular fossa present one the ventral surface of zygomatic arch. -Pterygoid fovea: on the medial aspect of mandibular ramus beneath the coracoid process medially for attachment of pterygoideus lateralis muscle. -Mandibular foramen: on medial aspect of mandibular ramus, represent entrance of mandibular canal. -Pterygoid fossa: rough area on the medial aspect of mandibular ramus beneath pterygoid fovea medially for attachment of pterygoideus medialis muscle. * Hyoid bone: Is situated chiefly between rami of the mandible and is extended caudally. Hyoid bone consists of 5 parts: 1. Basihyoid (body of hyoid bone): transverse short bar compressed dorsoventrally. It has a facet for articulation with ceratohyoid bone (small cornu). The rostral border carries medially lingual process which support the root of the tongue. The caudal border carries on each side the thyrohyoid. 2. Lingual process: projects rostromedially from the basihyoid and embedded in the root of the tongue. 3. Thyrohyoid: extend dorsocaudally from the lateral parts of basihyoid. Its caudal end has short cartilaginous prolongation connect with the rostral cornu of thyroid cartilage of larynx. 4. Ceratohyoid (small cornu): short rods directed dorsorostrally from each end of the basihyoid. The dorsal end articulate with stylohyoid. 5. Stylohyoid (large cornu): the largest part of the bone directed dorsocaudally and attach to styloid process of petrous part of temporal bone. The dorsal end of each stylohyoid have 2 angles: a. Articular angle: for articulation with styloid process. b. Muscular angle: for muscular attachment. CouPractical anatomy | Second lecture | Prof. Assis. Naziha Sultan Ahmed Page | 4 Epihyoid: cartilaginous part in small ages, present between ceratohyoid and stylohyoid in horse and ossify in old ages. Tympanohyoid: cartilaginous part present at the attachment of the stylohyoid with the styloid process. It’s very small (nodule) unite with stylohyoid in old ages. CouPractical anatomy | Second lecture | Prof. Assis. Naziha Sultan Ahmed Page | 5 CouPractical anatomy | Second lecture | Prof. Assis. Naziha Sultan Ahmed Page | 6 Skull of Horse/ Ventral Surface CouPractical anatomy | Second lecture | Prof. Assis. Naziha Sultan Ahmed Page | 7 Skull of Horse/ Ventral Surface CouPractical anatomy | Second lecture | Prof. Assis. Naziha Sultan Ahmed Page | 8 CouPractical anatomy | Second lecture | Prof. Assis. Naziha Sultan Ahmed Page | 9 Hyoid bone/ Bovine CouPractical anatomy | Second lecture | Prof. Assis. Naziha Sultan Ahmed Page | 10 .