A22- Muscles of Massication

Question 1

What is the process of chewing?

Answer 1

Mastication

Question 2

Why do we need to break down food stuff?

Answer 2

• in preparation of swallowing
• increase surface area for digestion
• to release chemicals for the sense of taste

Question 3

What does saliva do?

Answer 3

neutralises acid from food and plaque

Question 4

What muscle originates from the zygomatic arch and inserts into the angle of the mandible?

Answer 4

masseter

Question 5

what is the primary and secondary function of the masseter?

Answer 5

primary - jaw elevation

secondary - minor protrusion

Question 6

What is he innervation of masseter?

Answer 6

Vc motor root

Question 7

What is the origin and instertion of temporalis?

Answer 7

origin - inferior temporal lines

insertion - coronoid process

Question 8

what is the function of temporalis?

Answer 8

jaw elevation and retrusion

Question 9

The CN V3 motor root supplies innervation to which muscles of mastication?

Answer 9

masseter
temporalis 
medial and lateral pterygoids
mylohyoid 
anterior belly of digastric

Question 10

The upper head of the lateral pterygoid originates and inserts where?

Answer 10

origin - infra-temporal surface of the greater wing if the sphenoid

insertion - capsule and articular disc of TMJ

Question 11

What is the only muscle that does not cause jaw elevation and what does it do?

Answer 11

lateral pterygoid, it assists opening

Question 12

What muscle inserts into the head of the condyle and originates from the lateral aspect of the lateral plate?

Answer 12

the lower head of the lateral pterygoid

Question 13

What is the complex action of the lateral pterygoid inferior head?

Answer 13

it pulls the condyle forward
bilaterally - protrusion and opening
unilaterally - lateral excursion

Question 14

What is the origin and insertion of the medial pterygoid?

Answer 14

origin - medial aspect of the lateral plate

insertion - medial aspect of the angle of the mandible

Question 15

What is the function of the medial pterygoid?

Answer 15

jaw elevation (protrusion and lateral excursion)

Question 16

What muscles attach from the mandible to the hyoid?

Answer 16

genohyoid
mylohyoid
anterior belly of digastric

Question 17

What is the origin and insertion of the genohyoid?

Answer 17

origin - inferior mental spine an inferior genial tubercle

insertion - hyoid bone

Question 18

Describe the action of the genohyoid when the hyoid is fixed and loose.

Answer 18

fixed - jaw opening

loose - raises the hyoid up and out

Question 19

What is the innervation of the genohyoid

Answer 19

C1 (with hypoglossal)

Question 20

What is the origin and insertion of the mylohyoid?

Answer 20

origin - mylohyoid line on the internal aspect of the mandible

insertion - via the median raphe into the hyoid

Question 21

Describe the action of the mylohyoid when the hyoid is fixed and loose.

Answer 21

fixed - jaw opening

loose - raise the hyoid and the floor of mouth

Question 22

What are the other accessory muscles involved in mastication?

Answer 22

orbicularis oris

buccinator - keeps food in the mouth and directs food

Question 23

What is the origin and insertion the anterior belly of digastric?

Answer 23

origin - digastric fossa

insertion - hyoid bone

Question 24

Describe the action of the anterior digastric when the hyoid is fixed and loose.

Answer 24

fixed - jaw opening

loose - raise hypoid

Question 25

What are the hyoid stablisers?

Answer 25

stylohyoid
posterior belly of digastric
infrahyoids (omohyoid, strernohypid, thyrohyoid)