68. Muscles of mastication

Question 1

Identify

Answer 1

1. Temporalis muscle
2. Insertion of masseter muscle (cut away)
3. Buccinator muscle
4. Orbicularis oris muscle

Question 2

muscles of mastication

• are derived embryologically from ____
• are innervated by ___

Answer 2

• the 1st pharyngeal (branchial) arch
• the mandibular division of the trigeminal nerve (CN V3)

Question 3

Identify 1. O & I

Answer 3

1. Temporalis muscle

Origin: Temporalis muscle arises from the floor of the temporal fossa and the deep surface of the temporal fascia.

Insertion: The tip and medial surface of the coronoid process and anterior border of the ramus of the mandible.

Question 4

Identify 1. Action

Answer 4

1. Temporalis muscle

Action:

Elevates mandible
Retrudes mandible (posterior fibers)

Question 5

Identify 1. Innervation

Answer 5

1. Temporalis muscle

Innervation: Anterior and posterior deep temporal nn. from mandibular division of trigeminal n.

Question 6

Which muscle is the Main postural muscle that maintains mandible in rest position?

Answer 6

Temporalis muscle

Question 7

What are the 4 muscles of mastication?

Answer 7

1. Temporalis muscle
2. Masseter muscle
3. Medial pterygoid muscle
4. Lateral pterygoid muscle

Question 8

Identify

Answer 8

1. Masseter muscle
2. Parotid duct (cut)
3. Buccinator muscle
4. Temporalis muscle

Question 9

1 artery, 1 structure and nerves that pass superficial to masseter

Answer 9

Parotid duct, transverse facial a., and branches of facial n.

Question 10

Identify 1. O & I

Answer 10

1. Masseter muscle

Origin: Masseter muscle arises from the inferior border and medial surface of the zygomatic arch.

Insertion: Massester muscle attaches to the lateral surface of the mandible and lateral surface of the coronoid process.

Question 11

Identify 1. Action

Answer 11

1. Masseter muscle

Action: Masseter muscle closes the jaw by elevating the mandible.

Question 12

Identify 1. Innervation?

Answer 12

1. Masseter muscle

Innervation: Masseteric n. from mandibular division of trigeminal n.

Question 13

Identify

Answer 13

1. Masseter (deep head)
2. Masseter (superficial head)

Question 14

Structure that pierces the buccinator muscle?

Answer 14

the parotid duct which drains the parotid gland

Question 15

Elevation of the jaw (except masseter m.) also is assisted by the actions of ____ (2 muscles)

Answer 15

the temporalis and medial pterygoid muscles.

Question 16

Identify 1 - 3

Answer 16

1. Medial pterygoid muscle
2. Sphenomandibular ligament
3. Levator veli palatini muscle (cut)

Question 17

Identify 4 - 6

Answer 17

4. Tensor veli palatini muscle (cut)
5. Lateral pterygoid muscle
6. Pterygoid hamulus

Question 18

Identify 1. O & I

Answer 18

1. Medial pterygoid muscle

Origin: Medial pterygoid muscle arises from 2 slips. Its deep head arises from the medial surface of the lateral pterygoid plate and pyramidal process of the palatine bone. Its superficial head arises from the tuberosity of the maxilla.

Insertion: The fibers of the medial pterygoid muscle blend to attach to the medial surface of the ramus of the mandible

Question 19

Which artery runs superficial or deep to lateral pterygoid muscle?

Answer 19

Maxillary a.

Question 20

Medial pterygoid muscle arises from 2 slips.

• Its deep head arises from ___ AND ____
• Its superficial head arises from___

Answer 20

• the medial surface of the lateral pterygoid plate and pyramidal process of the palatine bone.
• the tuberosity of the maxilla.

Question 21

Identify 1. Actions

Answer 21

1. Medial pterygoid muscle

Actions:

• Depresses mandible
• Protrudes mandible
• Lateral excursion of mandible

Question 22

Identify 1. Nerve

Answer 22

1. Medial pterygoid muscle

Nerve: Medial pterygoid branch of mandibular division of trigeminal

Question 23

Identify

Answer 23

1. Deep head of the medial pterygoid m.
2. Superficial head of the medial pterygoid m.

Question 24

Identify

Answer 24

1. Deep head of the medial pterygoid m.

Question 25

Medial pterygoid muscle helps close the jaw by \_\_\_\_

Answer 25

elevating the mandible.

Question 26

With the lateral pterygoids, what do the 2 medial pterygoids do?

Answer 26

protrude the mandible.

Question 27

When 1 medial and 1 lateral pterygoid on the same side of the head act together, what are the actions of the mandible?

Answer 27

the mandible is protruded forward and to the opposite side

Question 28

Identify

Answer 28

1. Superior head of the lateral pterygoid m. 2. Inferior head of the lateral pterygoid m.

Question 29

Identify

Answer 29

1. Superior head of the lateral pterygoid m. 2. Inferior head of the lateral pterygoid m.

Question 30

Identify

Answer 30

1. Superior head of the lateral pterygoid m. 2. Inferior head of the lateral pterygoid m.

Question 31

Identify 1 → 2

Answer 31

1. **Lateral pterygoid muscle** 2. Articular disc of temporomandibular joint

Question 32

Identify 3 → 5

Answer 32

3. Sphenomandibular ligament 4. Medial pterygoid muscle 5. Buccinator muscle

Question 33

Identify 1. O & I

Answer 33

1. **Lateral pterygoid muscle** **Origin:** The superior head arises from the infratemporal surface and infratemporal crest of the greater wing of the sphenoid bone. The inferior head arises from the lateral surface of the lateral pterygoid plate. **Insertion:** the pterygoid fovea on the front of the neck of the mandible, articular disc, and capsule of the temporomandibular joint.

Question 34

1. **Lateral pterygoid muscle** * The superior head arises from \_\_\_\_ * The inferior head arises from \_\_\_\_

Answer 34

1. **Lateral pterygoid muscle** * the infratemporal surface and infratemporal crest of the greater wing of the sphenoid bone. * the lateral surface of the lateral pterygoid plate.

Question 35

Identify 1. Actions

Answer 35

1. **Lateral pterygoid muscle** **Actions:** * Depresses mandible * Protrudes mandible * Lateral excursion of mandible

Question 36

Identify 1. Innervation

Answer 36

1. **Lateral pterygoid muscle** Innervation: Lateral pterygoid branches (for each head) of mandibular division of trigeminal

Question 37

Which nerve passes between the 2 heads of lateral pterygoid muscle?

Answer 37

Buccal branch of trigeminal n.

Question 38

Lateral pterygoid muscle assists in opening the mouth by drawing ___ and ____ forward.

Answer 38

the condyle of the mandible and articular disc of the temporomandibular joint

Question 39

With the medial pterygoid of the same side, the lateral pterygoid protrudes the mandible. → The jaw is rotated to the opposite side, producing\_\_\_\_

Answer 39

a grinding movement.

Question 40

The other 3 muscles of mastication help close the jaw, whereas ____ opens the jaw

Answer 40

**Lateral pterygoid muscle**

Question 41

The other 3 muscles of mastication help close the jaw, whereas the lateral pterygoid opens the jaw. → At the beginning of this action, it is assisted by ___ (3 muscles)

Answer 41

the mylohyoid, digastric, and geniohyoid muscles.