Lecture 28 - Temporal fossae Flashcards
What does slicing involve?
Sharp edges coming together or shearing past each other
What bony structures make up the TMJ?
Condyle of mandible
Mandibular fossa of temporal bone
What divides the TMJ into ventral and dorsal halves?
Cartilaginous articular disc
What does the dorsal half of the TMJ capsule do?
Allows mandibular condyle to slide rostrally or caudally back into place
What does the ventral half of the TMJ capsule do?
Permits hinge like opening and closing
What prevents lateral displacement of the TMJ?
Lateral ligament
What prevents posterior displacement of the TMJ?
Retroarticular process
What prevents ventral displacement of the TMJ?
Joint capsule
Surround muscles
What produces lateral movements of the mandible?
Retractors on same side
Protruders on opposite side
What is different about the mandible in most domestic animals?
Not fused; joined by a symphysis which allows lateral movement and torsional movement
What are the four muscles of mastication?
Temporalis - Masseter - Medial pterygoid - Lateral pterygoid
What nerve innervates the muscles of mastication?
CN V3 - Mandibular nerve
What muscles act across the TMJ but arent muscles of mastication?
Cranial digastric and Mylohyoid
Where does the temporalis muscle originate?
Temporal fossa - some dibers on the lateral nuchal crest
Where does the Temporalis muscle insert?
Coronoid process of the mandible
What is the bilateral action of the Temporalis muscle/?
Jaw closing
What is the unilateral action of the temporalis muscle?
Broad origin allows differences in action based on portion of muscle bring used but most cause retraction
What is the origin of the masseter muscle?
Zygomatic arch
What is the insertion of the masseter?
Masseteric fossa and angular process of the mandible
What is the bilateral action of the masseter?
Jaw closing
What is the unilateral action of the masseter?
Superficial fibers - Protract
Deep fibers - Draw mandible directly laterally or retract
Where does the medial pterygoid originate?
Pterygopalatine fossa
Where does the medial pterygoid muscle insert?
Medial surface of mandibular ramus and angular process
What is the bilateral action of the medial pterygoid?
Jaw closing
What is the unilateral action of the medial pterygoid?
Protraction
What is the origin of the lateral pterygoid muscle?
Pterygopalatine fossa
What is the insertion point of the lateral pterygoid?
Capsule of the TMJ and the articular disk