Muscles of Mastication

Question 1

Temporalis

Answer 1

O: floor of temporal fossa and deep temporal fascia
I: coronoid process and ramus of mandible
A: elevates mandible; posterior fibers retract mandible
I: CN V

Question 2

Masseter

Answer 2

O: zygomatic arch
I: ramus of mandible and coronoid process
A: elevates and protrudes mandible; deep fibers retract it
I: CN V

Question 3

Lateral pterygoid

Answer 3

O: superior head- infratemporal surface of greater wing of sphenoid; inferior head- lateral pterygoid head
I: neck of mandible, articular disc and capsule of TMJ
A: together- protrude mandible, deep fibers retract; acting alone- each head produces side to side grinding movements
I: CN V

Question 4

Medial pterygoid

Answer 4

O: deep head- medial surface of lateral pterygoid plate and palatine bone; superficial head- tuberosity of maxilla
I: ramus of mandible, inferior to mandibular foramen
A: elevates mandible; together- protrudes mandible ; alone- protrudes side of jaw and grinding motion
I: CN V