Articulatory Muscles: Muscles of Mastication

Question 1

4 groups of articulatory muscles

Answer 1

Muscles of Facial expression

Muscles of the tongue

Muscles of the velopharyngeal mechanism

Muscles of mastication

Question 2

What does masticate mean?

Answer 2

means to chew

Muscles of mastication divided into two groups of muscles based on their function

Mandibular depressors (6)
Mandibular elevators (3)

Question 3

Mandibular Depressors (6)

Answer 3

Named because they depress or lower the mandible

1. Anterior belly of digastric
2. Posterior belly of digastric
3. Mylohyoid
4. Geniohyoid
5. Lateral or external pterygoid
6. Platysma

Some of these are also laryngeal muscles***

Question 4

Mandibular Elevators (3)

Answer 4

Named because they elevate or raise the mandible

1. Masseter
2. Temporalis
3. Medial or internal pterygoid

Question 5

Anterior Belly of Digastric

Answer 5

Recall that the anterior belly o digastric is also an extrinsic laryngeal muscle - suprahyoid group

As a group, extrinsic laryngeal muscles will have an effect on the larynx as a whole

As a suprahyoid muscle, the anterior belly of digastric will also ELEVATE or RAISE the LARYNX

Question 6

Posterior Belly of Digastric

Answer 6

Recall that the posterior belly of digastric is also part of the suprahyoid class of extrinsic laryngeal muscles

It will also ELEVATE or RAISE the larynx

Question 7

Mylohyoid

Answer 7

forms the floor of the mouth

It is believed that mylohyoid primarily functions as a laryngeal elevator (an extrinsic laryngeal muscle, suprahyoid group)

It is believed that mylohyoid has minimal effect as a mandibular depressor

Question 8

Geniohyoid

Answer 8

Part of the suprahyoid class of extrinsic laryngeal muscles

It will also raise or elevate the larynx

It lies deep to the mylohyoid

Question 9

Lateral or external pterygoid

Answer 9

This muscle will protrude the mandible by sliding the condyle inferiorly and anteriorly

Also assists in lowering or opening the mandible. Also moves the mandible side to side [laterally].

Question 10

Platysma

Answer 10

This is also a muscle that may have 2 functions:

1) Mandibular depressor

2) Muscle of facial expression (pulls lower lip down)

Origin: Fascia covering pectorals major and deltoid muscles

Course: superiorly

Question 11

Mandibular Elevators (3)

Answer 11

3 muscles serve as mandibular elevators, meaning they will RAISE or ELEVATE the MANDIBLE

1. Masseter
2. Temporalis
3. Medial or internal pterygoid

Question 12

Masseter

Answer 12

Very powerful jaw muscle

Elevates the mandible.

May also move the mandible laterally or side to side, as when chewing

Question 13

Temporalis

Answer 13

This muscle covers the temporal bone, one of the cranial bones

It will ELEVATE and RETRACT the mandible

Question 14

Medial or internal pterygoid

Answer 14

This muscle will form a sling with masseter in order to elevate or close the mandible