Occipital Bone Anatomy PDF

Occipital bone Unpaired Nuchal wall of skull Together=osseous surroundig spinal cord=foramen magnum  Squamous part Foramen magnum Lateral part left Basilar part Lateral part right Squamous part Lateral part left Lateral part right...

Occipital bone Unpaired Nuchal wall of skull Together=osseous surroundig spinal cord=foramen magnum  Squamous part Foramen magnum Lateral part left Basilar part Lateral part right Squamous part Lateral part left Lateral part right Foramen magnum Basilar part Squamous part  External sagittal crest External occipital protuberance Nuchal crest Internal occipital Collection of cerebrospinal flid Ruminant: prominent nuchal line protuberance External occipital crest Internal sagittal ridge: jsp Nuchal tubercles Lateral parts Hypoglossal canal Occipital condyles Articulate with atlas Paracondylar/jugular processes Provide muscular attachment Ventral condyloid fossa form end of hypoglossal canal Basilar part  Jugular foramen Muscular tubercles attachment of flexor muscles of head and neck cranial caudal fossa pas trouvé donc merde petrooccipital fissure horses and pig foramen lacerum Sphenoid bone Unpaired bone rostral part 2 similar segments each bone is composed of a median body and a pair of wings  Prespenoid External surface of wings contribute to formation of orbit + optical canal Basisphenoid  Squamous Prespenoid Lateral Basisphenoid Basal part Basisphenoid yeux-----fin tete  caudal alar foramen pointes en bas pterygoid process of the pterygoid bone ! alar canal rostral alar foramen carotid notch: passage for internal carotid artery oval notch: passage mandibular nerve spinous notch: middle meningeal artery foramen lacerum caudal border of each wing form rostral border of this foramen and form 3 notchs: carotid-oval-spinous abs in carnivor and ruminants abs in carnivor and ruminants so its function are remplaced by oval foramen and carotid canal in carnivores and oval foramen in ruminants caudal alar foramen Prespenoid Optic canal: passage of optic nerve vue de dessus la tête  Temporal bone paired bone Squamous-petrosal-tympanic part P and T also named pyramid fused in carni-ox separated in others mammals Squamous part Tympanic part Zygomatic process forming zygomatic arch base of ZP form articulating surface of the temporomandibular joint: articular tubercle mandibular fossa with retroarticular process Carnivores no articular tubercle, but well retro.p Retro foramen form end of temporal canal that house temporal venous sinus and meningeal arterial branches Zygomatic process retroarticular foramen Mandibular fossa retroarticular process  tympanic bulla: enclose tympanic cavity external acoustic meatus muscular process: prominent in horses and ruminants musculotubal canal: connect tympanic cavity to pharynx  c une vue du gauche mais de dedans petrosal part cerebellar fossa= cerebellum enclose inner ear medial surface is perforated by internal acoustic meatus, facial, vestibulocochlear nerves dog: canal of trigerminal nerve Types of joints  Fibrous joint Synarthrosis joints: are immovable or allow very limited movement. They are found where stability is crucial. cartilagenous joint Amphiarthrosis joints: allow limited movement and provide both flexibility and strength. They are typically connected by cartilage or a ligament. Synovial joint Diarthrosis joints (synovial joints): are freely movable and are the most common type of joint in the body. They are characterized by a synovial cavity filled with fluid that reduces friction during movement. 1. Fibrous Joints = synarthrosis (immovable joints) Types of Fibrous Joints: Syndesmoses: Bones are connected by a ligament or an interosseous membrane. These joints allow minimal movement. Example: the distal tibiofibular joint. Sutures: Found between the bones of the skull, these joints are immovable and bones are tightly bound by fibrous tissue. Gomphoses (Articulatio Dentoalveolaris): Specialized joints between teeth and their sockets in the maxilla or mandible. These are immovable and stabilized by the periodontal ligament. syndesmosis dense fibrous intermediate substance, organised like a true ligament, rarely ossify, ”less immobile" than sutures sutures shallow fibrous tissue between the bones, between membranous bones, more frequent, located mainly in the head, often ossify (synostosis) gomphosis/impactions the anchoring of the teeth roots in the dental alveoli by dense connective tissue (periodontal ligament) Young animal union btw bones and skull: fibrous junctions which ossify to form osseous suture lot are synchondrodid and remain cartilagenous In canine, frontal-parietal-occipital bone remain apart forming permanent fontanelles  Occipital bone joints: completed by interparietal bone joint to each of parietal bone by a serrate suture Shenoid bone joints: Basi and syn are united by intersphenoidal syncondrosis The presphenoid is joined by suture to: frontal-ethmoid-palatine-pterygoid-vomer bone Temporal bone joints: this joint is never transformed into a synostosis in horses and small ruminants squamous part joints: pyramid-occipital-parietal-spenoid-zygomatic-frontal bone  Parietal bone joints: frontal bone joints: sagittal suture to bone of opposite side interfrontal suture lambdoid suture to interparietal-occipital coronal suture to parietal bone squamous suture to temporal coronal suture to frontal 2. Cartilaginous Joints (Junctura Cartilaginea)= amphiarthrosis (slightly movable joints) Types of Cartilaginous Joints: Synchondrosis: Bones are connected by hyaline cartilage. These joints are usually temporary and allow very limited movement. Example: the epiphyseal plates in growing bones. Symphyses: Bones are connected by fibrocartilage. These joints allow limited movement and provide strength and flexibility. Example: the pubic symphysis and intervertebral discs.. 3. Synovial Joints (Junctura Synovialis): diarthrosis (freely movable joints). Characteristics of Synovial Joints: They have a cavity filled with synovial fluid (articular fluid). This fluid-filled cavity allows for a high degree of movement, making these joints the most mobile type in the body.