Muscles Of Mastication Acting On The Mandible

Question 0

Insertion of the temporalis

Answer 0

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

Question 1

Origin of the temporalis

Answer 1

Triangular muscle with broad attachment to floor of temporal fossa and deep surface of temporalis fascia

Question 2

Innervation of the temporalis

Answer 2

Anterior trunk of mandibular nerve (CN V3) via deep temporal nerves

Question 3

Action of temporalis

Answer 3

Elevates mandible, closing jaws

Posterior, more horizontal fibers are retractors of mandible

Question 4

Origin of the masseter

Answer 4

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

Question 5

Insertion of the masseter

Answer 5

Angle and lateral surface of ramus of mandible

Question 6

Innervation of masseter

Answer 6

Anterior trunk of mandibular nerve (CN V3) via masseteric nerve

Question 7

Actions of the masseter

Answer 7

Elevates mandible

Superficial fibers make limited contribution to protrusion of mandible

Question 8

Origin of the lateral pterygoid

Answer 8

Triangular two-headed muscle from (a) infratemporal surface and crest of greater wing of sphenoid and (b) lateral surface of lateral pterygoid plate

Question 9

Insertion of the lateral pterygoid

Answer 9

Superior 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 10

Innervation of the lateral pterygoid

Answer 10

Anterior trunk of mandibular nerve (CN V3) via nerves to lateral pterygoid

Question 11

Action of lateral pterygoid

Answer 11

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

Question 12

Origin of the medial pterygoid

Answer 12

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

Question 13

Insertion of the medial pterygoid

Answer 13

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

Question 14

Innervation of the medial pterygoid

Answer 14

Anterior trunk of the mandibular nerve (CN V3)via nerve to medial pterygoid

Question 15

Action of the medial pterygoid

Answer 15

Acts synergistically with masseter to elevate mandible
Contributes to protrusion
Alternate unilateral activity produces smaller grinding movements