Muscles of Mastication

Question 1

What are the muscles of mastication?

Answer 1

Temporalis
Masseter
Medial Pterygoid
Lateral Pterygoid
Masticatory accessory muscles

Question 2

Characteristics of the Muscles of Mastication

Answer 2

• 4 Pairs- temporalis, masseter, medial and lateral pterygoid
• Action: Depress, elevate, protrude, retract, lateral shifts
• Insert onto the mandible

Question 3

Embryonic origin of the muscles of mastication

Answer 3

First brachial arch/Pharyngeal Arch/Mandibular Arch

Question 4

Innervation of the muscles of mastication

Answer 4

Mandibular division of Trigeminal- V

Question 5

Action of the temporalis

Answer 5

Elevates mandible, closing mouth and clenching teeth and retracts mandible

Question 6

Origin of the temporalis

Answer 6

Temporal fossa, frontal and parietal bones

Question 7

Insertion of the temporalis

Answer 7

Coronoid Process and anterior border of the ramus

Question 8

Action of the masseter muscles

Answer 8

Elevates mandible, closing mouth and clenching teeth

Question 9

Origin and Insertion of the superficial head of masseter

Answer 9

Origin: Anterior 2/3 inferior border of zygomatic arch

Insertion: Lateral surface of angle of mandible

Question 10

Origin and Insertion of the deep head of the masseter

Answer 10

Origin: Posterior 1/3 inferior border and medial surface of zygomatic arch

Insertion: Lateral surface of ramus and coronoid process above the angle of the mandible

Question 11

Action of the medial pterygoid

Answer 11

Elevates mandible, closing mouth

Question 12

Origin and insertion of the superficial head of the medial pterygoid

Answer 12

Origin: Maxillary tuberosity
Insertion: Medial surface of ramus and angle of mandible

Question 13

Origin and Insertion of the deep head of the medial pterygoid

Answer 13

Origin: Medial surface of lateral pterygoid plate and edge of palatine bone
Insertion: Medial surface of ramus and angle of mandible

Question 14

Action of Lateral pterygoid

Answer 14

Contraction of both muscles= protrusion and slight depression
Contraction of one muscle= lateral shift of mandible

Question 15

Origin and Insertion of superior head of lateral pterygoid

Answer 15

Origin: Infratemporal surface of greater wing of sphenoid
Insertion: Articular disc of TMJ

Question 16

Origin and Insertion of Inferior head of lateral pterygoid

Answer 16

Origin: Lateral surface of lateral pterygoid
Insertion: Pterygoid fovea on condyle