1 E

Question 0

What are the four muscles of mastication?

Answer 0

Temporalis
Masseter
Medial Pterygoid
Lateral Pterygoid

Question 1

What cranial nerve innervates the muscles of mastication?

Answer 1

CN V (V3)

Question 2

Masseter OIA?

Answer 2

Origin: Zygomatic surface of maxilla (superficial) and the zygomatic arch (deep)
Insertion: Lateral surface of the ramus of the mandible
Action: Close the jaw by elevating the mandible

Question 3

Temporalis OIA?

Answer 3

Origin: Temporal fossa
Insertion: Medial and anterior surface of coronoid process and anterior surface of ramus of the mandible.
Action: Elevates the mandible and closes the jaw. Posterior fibers retract mandible.

Question 4

Lateral pterygoid OIA?

Answer 4

-Superior Head-
Origin: Lateral surface of greater wing of the sphenoid bone
Insertion: Neck of condyle of mandible, articular disk and capsule of temporomandibular joint
Action: Opens mouth by drawing condyle and disc forward (acting together: protrudes mandible; alternately: grinding)
-Inferior Head-
Origin: Lateral surface of lateral pterygoid plate of sphenoid bone
Insertion: Same as superior head
Action: Same as superior head

Question 5

Medial pterygoid OIA?

Answer 5

-Deep Head-
Origin: Medial surface of lateral pterygoid plate
Insertion: Medial surface of ramus and angle of the mandible
Action: Elevates mandible closing jaw, together protrudes mandible, alone protrudes one side of mandible, alternately grinding action
-Superficial Head-
Origin:
Insetion:
Action:

Question 6

What two things move in coordination with jaw movement?

Answer 6

Tongue and hyoid bone

Question 7

What are the three phases of the masticatory cycle?

Answer 7

Opening, Closing, Occlusal

Question 8

What happens during the opening phase of the masticatory cycle?

Answer 8

Relaxation of jaw elevators, contraction of jaw openers

Question 9

What happens during the closing phase of the masticatory cycle?

Answer 9

Jaw elevates and turns to working side

Question 10

What happens during the occlusal phase of the masticatory cycle?

Answer 10

Jaw nears closure, strongest forces are exerted, represents the longest component of the cycle

Question 11

WHat two muscles participate in protrusion?

Answer 11

Lateral pterygoid and medial pterygoid

Question 12

What four muscles participate in retraction of the jaw?

Answer 12

Posterior fibers of the temporalis, deep part of the masseter, geniohyoid and digastric

Question 13

What three muscles participate in elevation of the jaw?

Answer 13

Temporalis, masseter, and medial pterygoid

Question 14

What four muscles participate in depression of the mandible?

Answer 14

Digastric, geniohyoid, and mylohyoid, (also gravity)