TMJ

Question 1

TMJ osseous anatomy

• surfaces covered by…
• articular surfaces arthrokinematics
• what is between the joint surfaces

Answer 1

2 joint surfaces
surfaces covered by fibrocartilage
articular surfaces are both convex –> incongruent joint
articular disc interposed between the joint surfaces

Question 2

which part of the articular disk is the most vascularized

Answer 2

retrodiscal pad

Question 3

TM joint cavities

• locations/formed by what
• type of joints

Answer 3

inferior
-mandibular condyle and inferior surface of disc
-hinge joint
superior
-articular eminence and superior surface of the disc
-gliding joint

Question 4

muscles of mastication

-depressors

Answer 4

suprahyoids

lateral pterygoid

Question 5

muscles of mastication

-elevators

Answer 5

temporalis
masseter
medial pterygoid

Question 6

muscles of mastication

-lateral deviators

Answer 6

contralateral
-medial pterygoid
-lateral pterygoid
ipsilateral
-temporalis
-masseter (slightly)

Question 7

muscles of mastication

-protruders

Answer 7

bilateral masseter
medial pterygoid
lateral ptergoid

Question 8

muscles of mastication

-retruders

Answer 8

bilateral temporalis

suprahyoids

Question 9

articular disc

-characteristics

Answer 9

bi-concave fibrocartilage disc
avascular and insensate
-intermediate (central)
thin in central portion and thickens anterior and posterior

Question 10

articular disc functions

Answer 10

congruency for joint articulations
stability
minimizes loss of mobility
reduces friction
decreawses stress on TMJ

Question 11

primary ligament of the TMJ

Answer 11

lateral ligament

Question 12

lateral ligament

-functions

Answer 12

stabilizes the lateral aspect of the capsule

guides the condylar movement during mouth opening

Question 13

TMJ

• how far can the mouth open
• ratio of opening to lateral deviation and protrusion

Answer 13

40-50 mm

4:1 ratio

Question 14

TMJ arthrokinematics during early phase of opening

Answer 14

35-50% of the ROM
rolling motion moves the body of the mandible posterior and inferior
axis of rotation not fixed

Question 15

TMJ arthrokinematics during late phase of opening

Answer 15

final 50% of ROM
move from rotation to translatory motion
condyle and disc move together forward and inferior
maximal anterior stretch on the disc

Question 16

mouth closing

• how
• what structure assists with the closing

Answer 16

reverse order of opening
-translation (posterior) first
-rotation of the condyle last
tension from the retrodiscal lamina retracts the disc

Question 17

mouth motion normal ROM

Answer 17

depression: 40-50 mm
lateral deviation: 10-12
protrusion: 6-9
retrusion: 3

Question 18

TMJ and head/neck movements

• these two have a common dysfunction w/ what type of disorder
• how

Answer 18

whiplash-associated disorders

neck injury can impair jaw function and thereby disturb function

Question 19

what is TMD

Answer 19

collection of symptoms that involve the temporomandibular joint, or “jaw” and surrounding structures

Question 20

TMD symptoms

Answer 20

TMJ, face, ear, muscle, neck pain
tinnitus
dizziness
headache
joint sounds (popping, clicking, or grinding)
limited mandibular ROM

Question 21

age-related changes to the TMJ

Answer 21

preexisting degenerative changes resultant from deterioration of the TM joint may contribute to dysfunction
unresolved and chronic inflammation can result in loss of tissue function and damage to the TM joint