Mastication

Question 1

mandibular nerve of the trigeminal

Answer 1

provides motor innervation to the muscles of masticationn

Question 2

nerve to the mylohyoid

Answer 2

comes off inf alveolar before it heads into mandibular foramen. Motor innervation to the mylohyoid and ant digastric muscles.

Question 3

accessory muscles of mastication

Answer 3

mylohyoid and ant digastric

Question 4

masseter

Answer 4

origin: zygomatic bone and zygomatic process of the temporal bone
insert: ramus and angle of the mandible
elevates the mandible

Question 5

lateral pterygoid

Answer 5

origin: greater wing of the sphenoid bone and the pterygoidal plate
Insertion: condyle ans articular disc
protracts and depresses the mandible

Question 6

medial pterygoid

Answer 6

origin: pterygoid plate
insertion: inside of the angle of the mandible
elevates mandible

Question 7

mylohyoid

Answer 7

origin: deep surface of the mandible
insert: hyoid bone
Motor branch of V3
depress mandible

Question 8

anterior digastric

Answer 8

origin: inner surface of mandible
insert: hyoid
Motor branch of V3
depress mandible

Question 9

temporomandibular joint type

Answer 9

modified hinge: condyle of the mandible fits into the mandibular fossa of the temporal bone

disc of connective tissue between the 2 bones, slightly moveable

has a surrounding capsule

Question 10

TMJ movement

Answer 10

rotation: depression and elevation
translational: protrusion and retraction
side to side movement

Question 11

stable position of TMJ

Answer 11

when the jaw is elevated

Question 12

TMJ ligaments (3)

Answer 12

lateral temporomandibular: part of capsule, prevents excessive side to side mvmt

stylomandibular: prevents excessive protrusion and depression
sphenomandibular: prevents excessive depression

Question 13

1st step of mastication

Answer 13

1. move mandibular condyle forward onto the articular process of the temporal bone. Lat pterygoid protracts mandible (attached tp condyle and articular disc). Rotation and translation. Condyle depressed (rotation) and then protruded (translation)

Question 14

2nd step of mastication

Answer 14

opening wider. mylohyoid and ant digastric depress the mandible further. Very unstable, jaw can be dislocated in the front of the articular tubercle. Lig’s can become stretched. Could lead to TMJ syndrome which could cause pain and clicking

Question 15

3rd step of mastication

Answer 15

return to stable position. Ant temporalis, masseter, and medial pterygoid elevate the mandible. Post tempoalis is the retractor. Jaw returns to stable position in mandibular fossa.

Question 16

incisal chewing

Answer 16

condyles rotate forward on both sides and depress the mandible symmetrically.
to return: mandibular condyles rotate and the condyles are elevated

Question 17

side to side chewing

Answer 17

one condyle is forward on the articular tubercle and the other is not. assymetrical

Question 18

anterior 2/3 of tongue innervation

Answer 18

general sensation from V3 (lingual). taste and special sensation from facial

Question 19

post 1/3 of tongue innervation

Answer 19

general sensation and taste from CNIX (glossopharyngeal)

Question 20

Motor to tongue

Answer 20

hypoglossal nerve CNXII

• arises from the medulla
• two of them

Question 21

genioglossal muscles

Answer 21

pull the tongue forward when you stick it out, innervated by hypoglossal

Question 22

lesion to hypoglossal

Answer 22

will cause the tip of the tongue to move toward the side of the lesion. Genioglossus on the affected side not working; cant pull the tongue forward on that side. Important clinically to stick tongue out to check the integrity of the hypoglossal and the medulla.