Muscles of Mastication and Facial Expression

Question 1

What muscles move the mandible

Answer 1

Temporalis, Masseter, lateral pterygoid, and medial pterygoid

Question 2

What muscles elevate and and retract the mandible

Answer 2

Elevate= masseter and the temporalis

Retracts= temporalis

Question 3

How does the lateral pterygoid position the mandible

Answer 3

Say lateral

It opens (depresses) the mandible, this is the only muscle of mastication that does this

Question 4

How does the medial pterygoid position the mandible

Answer 4

Say medial

It closes (elevates) the mandible

Question 5

Together what does the pterygoids do

Answer 5

move the jaw in a side to side motion to grind food

Question 6

What nerve innervates all the muscles of mastication

Answer 6

Mandibular (V3) of the trigeminal nerve (CN3)

Question 7

Where do the muscles of facial expression originate

Answer 7

the skull

Question 8

What cranial nerve innervates all the the muscles of facial expression

Answer 8

CN 7 (facial)

Question 9

What are the 5 Branches of the cranial nerve 7 (facial)

Answer 9

The= Temporal
Zoo= Zygomatic
Bought=Buccal
More = Mandibular
Camels= Cervical

Question 10

Describe the occipitofrontalis muscle in terms of origin, insertion, action and innervation

Answer 10

Origin

• Occipital belly at the occipital lobe
• Frontal belly at the galea aponeurotica

Insertion

• Occipital belly galea aponeurotica
• Frontal belly fascia and skin above the eyes and nose

Action: raises eyebrows and wrinkles forehead skin

Innervated: temporal branch of CN 7

Question 11

Describe the zygomaticus major and minor muscles in terms of origin, insertion, action and innervation

Answer 11

Origin: both at the zygomatic bone

Insertion:

• Major= skin and muscle at the edge of the mouth
• Minor= upper lip

Action:

• Major=draw angle of the mouth up as in smiling
• Minor=raise upper lip exposing maxillary teeth

Innervation: zygomatic and buccal branch of CN7

Question 12

Describe the levator labii muscle in terms of origin, insertion, action and innervation

Answer 12

Origin: N/A

Insertion: skin at angle of the mouth and orbicularis oris (muscle around the lip)

Action: raises upper lip

innervation: zygomatic branch of CN7

Question 13

Describe the depressor labii muscle in terms of origin, insertion, action and innervation

Answer 13

origin: N/a
insertion: skin of lower lip
action: lowers the lower lip
innervation: mandibular branch of CN7

Question 14

Describe the depressor anguli oris muscle in terms of origin, insertion, action and innervation

Answer 14

origin: n/a
insertion: angle of the mouth
action: frowning, brings angle of the mouth laterally and inferiorly
innervation: mandibular branch of CN7

Question 15

Describe the orbicularis oris muscle in terms of origin, insertion, action and innervation

Answer 15

origin: muscle fibers encircling the opening of the mouth
insertion: skin at the corner of the mouth
action: shapes lips during speech, closes protrudes lips(duck face), compresses lips against teeth
innervation: buccal branch of CN 7

Question 16

Describe the risorius muscle in terms of origin, insertion, action and innervation

Answer 16

origin: n/a
insertion: skin at the angle of the mouth
action: grimacing look, draws angle of the mouth laterally
innervation: buccal branch of CN 7

Question 17

Describe the buccinator muscle in terms of origin, insertion, action and innervation

Answer 17

origin: n/a
insertion: orbicularis oris
action: assists in chewing by keeping food between the teeth, presses cheeks against teeth and lips , blowing motion
innervation: buccal branch of CN7

Question 18

Describe the mentalis muscle in terms of origin, insertion, action and innervation

Answer 18

origin: n/a
insertion: skin of chin
action: pouting face, elevates and protrudes the lower lip
innervation: mandibular branch

Question 19

Describe the platysma muscle in terms of origin, insertion, action and innervation

Answer 19

origin: n/a
insertion: mandible, angle of the mouth, skin of the lower face
action: draws outer part of the lower lip inferiorly and posteriorly as in pouting and depressing mandible
innervation: cervical branch of CN 7

Question 20

Describe the orbicularis oculi muscle in terms of origin, insertion, action and innervation

Answer 20

origin: n/a
insertion: circular path around the orbit
action: closes and squints the eye, elevates upper eyelid, depresses lower eyelid
innervation: temporal and zygomatic branch of CN 7

Question 21

True or false the levator palpebrae superioris (opens the eye) is a muscle of facial expression

Answer 21

False

Question 22

Describe the corrugator supercilii muscle in terms of origin, insertion, action and innervation

Answer 22

origin: n/a
insertion: skin of eyebrow
action: draws eyebrows inferiorly and medially, wrinkles forehead
innervation: temporal branch of CN 7

Question 23

What 2 facial muscles of facial expression are innervated by 2 branches of the CN7

Answer 23

orbicularis oculi

zygomaticus major and zygomaticus minor