Muscles of Mastication (acting on TMJ)

Question 1

What 4 movements can the mandible do?

Answer 1

1. depression
2. elevation
3. protraction
4. retraction

Question 2

What are the 4 muscles of mastication?

Answer 2

1. temporalis m.
2. masseter m.
3. lateral pterygoid m.
4. medial pterygoid m.

Question 3

Temporalis m.
O:
I: (2)

Answer 3

O: temporalis fossa

I:

1) coronoid process
2) anterior border of the ramus of mandible

Question 4

Temporalis m.
Innerv:
Function:

Answer 4

Innerv: V3-mandibular division of the trigeminal n.

Function:

1) closes the jaw
2) posterior portion retracts the mandible

Question 5

Masseter m.
O: (2)
I:

Answer 5

O:

1) inferior margin & deep surface of the zygomatic arch
2) zygomatic process of maxilla

I: angle & ramus of the mandible

Question 6

Masseter m.
Innerv:
Function:

Answer 6

Innerv: V3-mandibular division of the trigeminal n.

Function: closes the jaw

Question 7

Lateral Pterygoid m.

O: (2)

Answer 7

O:

1) superior head: infratemporal surface of the greater wing of the sphenoid bone
2) inferior head: lateral surface of the lateral pterygoid plate

Question 8

Lateral Pterygoid m.
Innerv:
Function:

Answer 8

Innerv: V3-mandibular division of the trigeminal n.

Function:

1) protrudes the mandible
2) moves mandible from side to side

Question 9

Medial Pterygoid m.
O:
I:

Answer 9

O: medial surface of the lateral pterygoid plate
I: medial surface of the ramus & angle of the mandible

Question 10

Medial Pterygoid m.
Innerv.:
Function:

Answer 10

Innerv: V3-mandibular division of the trigeminal n.

Function:

1) closes the jaw
2) acting alone it pulls the chin to the opposite side
3) when acting alternately it causes grinding

Question 11

What artery in the face is derived from the external carotid artery?

Answer 11

facial a.

Question 12

Which is NOT a description of the Facial Artery?

1. crosses the inferior mandible just anterior to the masseter m.
2. usually grooves bone; can feel the pulse here
3. crosses mandible only
4. runs deep to zygomaticus major and reaches the eye

Answer 12

3. crosses mandible only

* crosses mandible, buccinator, & maxilla