TMJ

Question 1

what kind of joint is the TMJ

Answer 1

synovial joint (divided into hinge and gliding)

Question 2

what are the articulations of the TMJ

Answer 2

between head of mandible and mandibular fossa and articular tubercle on the squamous part of the temporal bone

Question 3

why is the TMJ a modified synovial joint

Answer 3

includes a small disc

Question 4

what does the small disc in the TMJ permit

Answer 4

gliding movements between the head of the mandible, mandibular fossa and articular tubercle

Question 5

the TMJ is surrounded by

Answer 5

fibrous capsule

Question 6

what is the nerve supply of the TMJ

Answer 6

auriculotemporal and masseteric

Question 7

what covers the articular surfaces of the TMJ

Answer 7

fibrocartilage (membranous ossification)

Question 8

what ligaments reinforce the TMJ

Answer 8

lateral temporomandibular ligament

sphenomandibular and stylomandibular ligaments (medially)

Question 9

what muscle attaches to the articular disc and capsule of the TMJ

Answer 9

lateral pterygoid

Question 10

what movements can take place between the head of the mandible and the mandibular fossa/disc

Answer 10

simple hinge movements

Question 11

what happens at the TMJ to permit the mouth to open more fully

Answer 11

head of the mandible is pulled forwards towards the articular tubercle by lateral pterygoid

Question 12

the close the mouth what action must occur

Answer 12

head of mandible is pulled backwards away from the articular tubercle by posterior fibres of temporalis

Question 13

what muscle causes head of mandible to be pulled backwards away from the articular tubercle

Answer 13

posterior fibres of temporalis

Question 14

what does the articular disc do to the TMJ

Answer 14

divides the cavity

increases the congruency of the articular surfaces allowing a bigger, smoother movement

Question 15

the joint cavity of the TMJ is divided by

Answer 15

fibrous articular disc

Question 16

where does depression and elevation occur at the TMJ

Answer 16

between head of mandible and disc (hinge)

Question 17

where does protrusion and retraction occur at the TMJ

Answer 17

between disc and mandibular fossa and articular process (gliding)

Question 18

what happens to close the mouth

Answer 18

elevation and retraction pull condyle backwards

Question 19

what happens to open mouth

Answer 19

depression and protrusion to slide disc and condyle forwards towards tubercle

Question 20

what occurs in chewing

Answer 20

asynchronous gliding

Question 21

what occurs in elevation of the mandible

Answer 21

head of mandible and disc move backward and head rotates on lower surface of disc

Question 22

what muscles cause elevation of the mandible

Answer 22

temporalis
masseter
medial pterygoid

Question 23

what occurs in depression of the mandible

Answer 23

head of mandible rotates on undersurface of articular disc and mandible is pulled forward

Question 24

what muscles cause depression of the mandible

Answer 24

lateral pterygoid
digastric
geniohyoid
mylohyoid
(gravity)

Question 25

what happens in protrusion of the mandible

Answer 25

articular disc and head of mandible move forward

movement in upper part of cavity

Question 26

what muscles cause protrusion of the mandible

Answer 26

lateral pterygoid and medial assists

Question 27

what occurs in retrusion of the mandible

Answer 27

articular disc and head of mandible pulled backward into mandibular fossa

Question 28

what muscles cause retrusion of the mandible

Answer 28

posterior fibres of temporalis

Question 29

what occurs in lateral chewing

Answer 29

protrusion and retrusion combined

Question 30

what muscles cause lateral chewing

Answer 30

pterygoids

Question 31

what assists in depression of the mandible

Answer 31

gravity and suprahyoid muscles

Question 32

what muscle does not move the mandible but aids in the process of eating

Answer 32

buccinator

Question 33

how does buccinator aid in the process of eating

Answer 33

forms the lateral walls of the oral cavity and must be moved during chewing or you will accidentally bite the inside of cheek