Temporal and Infratemporal Fossae Muscles

Question 1

Temporalis Origin

Answer 1

floor of temporal fossa and deep surface of temporal fascia

Question 2

Temporalis Insertion

Answer 2

Narrow attachment to tip and medial surface of coronoid process and anterior border of ramus of mandible

Question 3

Temporalis Innervation

Answer 3

Anterior trunk of mandibular nerve(CN V3)

Question 4

Temporalis Action

Answer 4

Elevates mandible, closing jaws; posterior, more horizontal fibers are primary retractors of mandible

Question 5

Masseter Origin

Answer 5

Quadrate muscle attaching to inferior border and medial surface of maxillary process of zygomatic arch

Question 6

Masseter Insertion

Answer 6

Angle and lateral surface of ramus of mandible

Question 7

Masseter Innervation

Answer 7

Anterior trunk of mandibular nerve(CN V3)

Question 8

Masseter Action

Answer 8

Elevates mandible, closing jaws; superficial fibers make limited contribution to protrusion of mandible

Question 9

Medial Pterygoind Origin

Answer 9

Quadrangular two-headed muscle from (1) medial surface of lateral pterygoid plate and pyramidal process of palatine bone and (2) tuberosity of maxilla

Question 10

Medial Pterygoind Insertion

Answer 10

Medial surface of ramus of mandible, inferior to mandibular foramen; in essence, a “mirror image” of ipsilateral masseter, two muscles flanking ramus

Question 11

Medial Pterygoind Innervation

Answer 11

Anterior trunk of mandibular nerve(CN V3)

Question 12

Medial Pterygoind Action

Answer 12

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

Question 13

Lateral Pterygoid Origin

Answer 13

triangular two-headed muscle from (1) infratemporal surface and crest of greater wing of sphenoid and (20 lateral surface of lateral pterygoid plate

Question 14

Lateral Pterygoid Insertion

Answer 14

Upper head attaches primarily to joint capsule and articular disc of TMJ; inferior head attaches primarily to pterygoid fovea on anteromedial aspect of neck of condyloid process of mandible

Question 15

Lateral Pterygoid Innervation

Answer 15

Anterior trunk of mandibular nerve(CN V3)

Question 16

Lateral Pterygoid Action

Answer 16

Acting bilaterally, protracts mandible and depresses chin; acting unilaterally, swings jaw toward contralateral side; alternate unilateral contraction produces larger lateral chewing movements