Muscles of Mastication AIAs

proximal attachment of temporalis

floor of temporal fossa and deep surface of temporal fascia

distal attachment of temporalis

tip and medial surface of coronoid process and anterior border of ramus of mandible

innervation of temporalis

mandibular nerve (CN V3)

action of temporalis

elevates mandible, closing jaw; posterior, more horizontal fibers contribute to retrusion of mandible

proximal attachment of masseter

inferior border and medial surface of maxillary process of zygomatic bone and the zygomatic arch

distal attachment of masseter

angle and lateral surface of ramus of mandible

innervation of masseter

mandibular nerve (CN V3)

action of masseter

elevates mandible, closing jaw; superficial fibers make limited contribution to protrusion of mandible

proximal attachment of lateral pterygoid

infratemporal surface and crest of greater wing of sphenoid and lateral surface of lateral pterygoid plate

distal attachment of lateral pterygoid: superior head

joint capsule and articular disc of TMJ

distal attachment of lateral pterygoid: inferior head

pterygoid fovea of anteromedial aspect of neck of condyloid process of mandible

innervation of lateral pterygoid

mandibular nerve (CN V3)

action of lateral pterygoid: bilaterally

protracts mandible and depresses chin

action of lateral pterygoid: unilaterally

swings jaw toward contralateral side; alternate unilateral contraction produces larger lateral chewing movements

proximal attachment of medial pterygoid

medial surface of lateral pterygoid plate and pyramidal process of palatine bone and tuberosity of maxilla

distal attachment of medial pterygoid

medial surface of ramus of mandible, inferior to mandibular foramen

innervation of medial pterygoid

mandibular nerve (CN V3)

action of medial pterygoid

acts with masseter to elevate mandible; contributes to protrusion; alternate unilateral activity produces smaller grinding movements