Muscles of Mastication*

Question 1

What are the two superficial muscles?
And what does superficial mean?

Answer 1

Masseter and Temporalis
Superficial means it lies beneath the skin/easy to feel.

Question 2

What are the two deep muscles?

Answer 2

Medial and Lateral Pterygoid

Question 3

What is the temporomandibular joint?

Answer 3

A soft cartilage disk acts as a cushion between the bones of the joint, so it can move smoothly.

Question 4

What does the TMJ do?

Answer 4

It acts as a sliding hinge, connecting the jawbone to the skull. This helps elevate and depress the jaw.

Question 5

What is the role of the condyle?

Answer 5

The condyle sits in the concave glenoid cavity and is stable. When we open our mouth the condyle slides forward on to the articular eminence and becomes unstable.

Question 6

What forms the TMJ?

Answer 6

The TMJ is formed by the underside of the temporal bone and head of mandibular condyle.

Question 7

What is the articular disc?

Answer 7

It is a thin oval plate between the condyle of the mandible and the mandibular fossa. It is unique to the TMJ.

Question 8

Explain temporalis muscle of mastication.

Answer 8

It elevates and retracts the mandible. Attached to the lateral (away from the midline) aspect of the skull and coronoid process of the mandible.

Question 9

Explain masseter muscle of mastication.

Answer 9

It is a powerful elevator of the mandible. It is attached to the zygomatic arch and lateral aspect of mandibular ramus.

Question 10

Explain the lateral (away from middle) pterygoid muscle. And what it is attached to.

Answer 10

Protrudes the mandible.

Attached to the lateral side of the lateral pterygoid plate and neck of the condyle.

Question 11

Explain the medial (towards middle) pterygoid muscle. And what it is attached to.

Answer 11

A powerful elevator of the mandible.

Attached to the medial side of lateral pterygoid plate.

Question 12

Which 3 muscles elevate the mandible?

Answer 12

Temporalis, Masseter and the medial pterygoid.

Question 13

Which muscle retracts the mandible?

Answer 13

Temporalis

Question 14

Which muscle protrudes the mandible?

Answer 14

Lateral pterygoid

Question 15

What are the four pairs of muscles of mastication supplied by?

Answer 15

Motor branches of V3 mandibular branch of trigeminal.

Question 16

What does the suprahyoid muscle do?

Answer 16

These muscles contribute to swallowing and mastication. Referred to as an accessory muscle of mastication.

Question 17

What does the infrahyoid muscle do?

Answer 17

It is a muscle below the hyoid bone. It is involved in swallowing through movement of the larynx.

Question 18

Explain the process of depression of the mandible?

Answer 18

The infrahyoid and suprahyoid contracting together stabilize the hyoid bone.

The suprahyoid then pulls the mandible down and the lateral pterygoids protrude the mandible = downward movement of the mandible.

Question 19

What is the function of the buccinator?

Answer 19

This muscle forms part of the wall of the oral cavity. It compresses the cheeks against the teeth holding food between teeth during mastication (chewing, blowing, suckle actions).

Question 20

What is the function of the orbicularis oris?

Answer 20

Contributes to the shape of the lips. Contraction of this muscle closes and protracts the lips.