Muscles of Mastication

Question 1

Masseter

Answer 1

origin: zygomatic arch
insertion: lateral angle of the mandible
innervation: CN V3 (massenteric n.)
action: elevates mandible

Question 2

Temporalis

Answer 2

origin: temporal fossa and temporal fascia
insertion: coronoid process, ramus of mandible down to the 3rd molar tooth
innervation: CN V3 (deep temporal nn.)
action: elevate and retract mandible

Question 3

Medial Pterygoid

Answer 3

origin: deep head: medial side of lateral pterygoid plate and pyramidal process of the palatine bone. superficial head: tuberosity and pyramidal process of the palatine bone
insertion: medial angle of the mandible
innervation: n. to the medial pterygoid from CN V3
action: elevate and laterally move the mandible

Question 4

Lateral Pterygoid

Answer 4

origin: upper head: roof of the infratemporal fossa. lower head: lateral surface of the lateral pterygoid plate
insertion: upper head: TMJ disc. lower head: fovea of the mandible.
innervation: n. to the lateral pterygoid from CN V3
action: protrude and laterally move the mandible.