4.1. Muscles Of The Head

Question 1

What roles do muscles perform in the head?

Answer 1

Eating - mastication, keep food in oral cavity, push food toward eosophaghus
Speech
Non-verbal expression
Move eyes
Protect ears
Maintain airway

Question 2

What are the 4 muscles of mastication?

Answer 2

Massetter
Temporalis
Medial pterygoids
Lateral pterygoids

*2 of each, so actually 8 muscles in total

Question 3

What is the joint where movement occurs for mastication?

Answer 3

Temporomandibular joint

Question 4

What nerve innervates the muscles of mastication?

Answer 4

Trigeminal nerve - V3: maxillary branch

Question 5

What movements can occur at the temporomandibular joint?

Answer 5

Elevation/depression
Protrusion/retrusion
Lateral incursion

Question 6

What is the O/I/A of the Temporalis muscle?

Answer 6

O: temporal fossa
I: Coronoid process & angle of mandible
A: Lateral incursion (on same side - ipsilateral)
Elevation of mandible
Retraction (oblique fibres)

Question 7

What is the O/I/A of the massetter?

Answer 7

O: Zygomatic arch and maxillary process of zygomatic bone
I: angle and lateral surface of ramus of mandible
A: Elevation of mandible

Question 8

What is the O/I/A of the medial pterygoids?

Answer 8

O: medial surface of lateral pterygoids plate & tuberosity of maxilla & pyramidal process of palatine bone
I: medial surface of ramus of mandible
A: Elevate mandible (bilateral)
Lateral incursion to contralateral side (unilateral)

Question 9

What is the O/I/A of the lateral pterygoids?

Answer 9

O: greater wing of sphenoid & lateral surface of lateral pterygoid plate
I: condyloid process of mandible and joint disc/capsule of TMJ
A: protrusion of mandible (bilateral)
Lateral incursion to contralateral side (unilateral)