Muscles of Mastication

Question 1

where does the condyle sit?

Answer 1

glenoid fossa
behind articular eminence

Question 2

what bone is the articular eminence apart of?

Answer 2

temporal bone

Question 3

what TMJ movement is jaw opening?

Answer 3

hinge

Question 4

what TMJ movement is wide jaw opening?

Answer 4

hinge and slide

Question 5

what TMJ movement is protrusion?

Answer 5

slide

Question 6

what TMJ movement is lateral excursion?

Answer 6

lateral movement and rotation around vertical axis

translation

Question 7

dentate chewing forces?

Answer 7

70-150N

Question 8

edentulous chewing forces?

Answer 8

4-55N

Question 9

maximum clenching forces between molars?

Answer 9

500-700N

Question 10

where do you find the muscles of mastication?

Answer 10

between skull and mandible

Question 11

what are the muscles of mastication?

Answer 11

masseter
temporalis
medial pterygoid
lateral pterygoid

Question 12

origin and insertion of the superficial masseter?

Answer 12

origin: zygomatic arch
insertion: angle/ ramus of mandible

Question 13

action of the superficial masseter?

Answer 13

jaw elevation (closing)
minor protrusion

Question 14

innervation of superficial masseter?

Answer 14

Vc motor root - masseteric nerve

Question 15

origin and insertion of the deep masseter?

Answer 15

origin: inner aspect of zygomatic arch
insertion: angle/ ramus of mandible

Question 16

action of deep masseter?

Answer 16

jaw elevation (closing)

Question 17

innervation of deep masseter?

Answer 17

Vc motor root - masseteric nerve

Question 18

origin and insertion of temporalis?

Answer 18

origin: inferior temporal line and fascia
insertion: coronoid process

Question 19

action of temporalis?

Answer 19

jaw elevation and retrusion (posterior fibres)

Question 20

innervation of temporalis?

Answer 20

Vc motor root - deep temporal nerve

Question 21

origin and insertion of upper head lateral pterygoid?

Answer 21

origin: infratemporal surface of greater wing of sphenoid
insertion: capsule and articular disc of TMJ

Question 22

origin and insertion of lower head of lateral pterygoid?

Answer 22

origin: lateral aspect of lateral pterygoid plate
insertion: pterygoid fovea below head of condyle

Question 23

action of lateral pterygoid?

Answer 23

initial opening (hinge in lower joint space, suprahyoids only)

wide opening (anterior and inferior translation of condyle, assisted by inferior lateral pterygoids)

Question 24

innervation of lateral pterygoid?

Answer 24

Vc motor root - nerve to lateral pterygoid

Question 25

function of lower head of lateral pterygoid?

Answer 25

pulls condyle forward bilateral protrusion and assisted opening unilateral excursion

Question 26

function of super head of lateral pterygoid?

Answer 26

active during retrusion and closing

Question 27

origin and insertion of medial pteryoid?

Answer 27

origin: medial aspect of lateral pterygoid plate and maxillary tuberosity insertion: medial aspect of ramus/ angle of mandible

Question 28

action of medial pterygoid?

Answer 28

jaw elevation assists protrusion and lateral excursions (unilateral)

Question 29

innervation of medial pterygoid?

Answer 29

Vc motor root - nerve to medial pterygoid

Question 30

origin and insertion of geniohydoid?

Answer 30

origin: inferior mental spine and inferior genial tubercle insertion: hyoid bone

Question 31

action of geniohyoid?

Answer 31

when hyoid fixed: jaw opening and retrusion when hyoid not fixed: raise and forward hyoid

Question 32

innervation of geniohyoid?

Answer 32

C1 (with hypoglossal)

Question 33

where is the mylohyoid?

Answer 33

median raphe

Question 34

action of mylohyoid?

Answer 34

when hyoid fixed: jaw opening when hyoid not fixed: raise hyoid and FOM

Question 35

innervation of mylohyoid?

Answer 35

Vc motor root - nerve to mylohyoid (branch of IAN)

Question 36

origin and insertion of anterior belly of digastric?

Answer 36

origin: digastric fossa insertion: intermediate tendon

Question 37

action of anterior belly of digastric?

Answer 37

hyoid fixed: jaw opening hyoid not fixed: raises hyoid

Question 38

innervation of anterior belly of digastric?

Answer 38

Vc motor root - via nerve to mylohyoid (branch of IAN)

Question 39

what are the hyoid stabalisers?

Answer 39

infrahyoids posterior digastric stylohyoid

Question 40

what are the infrahyoids?

Answer 40

omohyoid thyrohyoid sternohyoid

Question 41

what are other muscles involved in mastication?

Answer 41

orbicularis oris (oral sphincter) buccinator (along with the tongue)