Mastication SDL Flashcards
Which 4 muscles are used for mastication?
Temporalis
Masseter
Lateral pterygoid (assisted by digastric muscle)
Medial pterygoid
What action do the temporalis and masseter carry out?
Closing the mouth
What is the function of the lateral pterygoid and digastric muscle?
Opening the mouth
What is the function of the medial pterygoid?
minor role in closing the mouth, main role is medial and lateral movement of the mandible.
At rest where does the head of the mandible rest?
The glenoid fossa of the temporal bone aka the mandibular fossa
What feature, continuous with the lateral pterygoid muscle, lies in the temporomandibular joint?
Disc of fibrocartilage
Is it the anterior of posterior aspect of the lateral pterygoid muscle that is mobile?
Posterior (at TMJ)
Where does the tendon of the mandible insert?
Pterygoid fovia and intraartiular disc and capsule of the TMJ
What is the action of the lateral pterygoid and posterior digastric muscles when the mouth opens?
Lateral pterygoid contracts to pull the insertion of the mandibular tendon anteriorly, posterior digastric contracts to draw the mandible downwards and the pulls the inferior part posteriorly.
Where is the temporalis muscle?
on the lateral surface of the skull
What happens when the temporalis muscle contracts?
It elevates and retracts the mandible
What does contraction of one medial pterygoid muscle do?
Swings the mandible to the opposite side.
What is the innervation of the muscles of mastication?
Mandibular division of the trigeminal nerve (CNV) except posterior belly of the digastric which is supplied by the facial nerve (CNVII)
