TMJ

Question 0

Where does the condyles of the mandible sit?

Answer 0

Mandibular fossa

Question 1

What are the articular structures of the mandible?

Answer 1

Posteriorly - postglenoid tubercle

Anteriorly - articular eminence

Question 2

Which of the two articular surfaces is the primary surface meant to sustain high forces?

Answer 2

Articular eminence

Question 3

What type of cartilage does the articular eminence contain?

Answer 3

Fibrocartilage (not hyaline because hyaline cartilage cannot repair itself)

Question 4

What type of cartilage can repair and remodel itself?

Answer 4

Fibrocartilage

Question 5

What is the shape of the TMJ joint?

Answer 5

Convex on concave

Question 6

What is the shape of the mandible?

Answer 6

Convex

Question 7

What is the shape of the articular eminence?

Answer 7

Convex

Question 8

What is the shape of the mandibular fossa?

Answer 8

Concave

Question 9

How do you palpate the TMJ?

Answer 9

Through the external meatus to feel for the posterior aspect of the mandibularcondyles

Question 10

What is the function of the articular disc?

Answer 10

Needed due to an incongruent joint

Question 11

What are the two parts of the articular disc and what type of joint are they?

Answer 11

1. Inferior - hinge joint (spins)

2. Superior - gliding joint (glides)

Question 12

What comprises the inferior TMJ?

Answer 12

Mandibular condyle and the inferior surface of the articular disc

Question 13

What comprises the superior TMJ?

Answer 13

Articular eminence and the superior surface of the articular disc

Question 14

What is the function of the articular disc?

Answer 14

Increases stability, minimizes loss of mobility, reduces friction, and decreases biomechanical stress

Question 15

Can the articular disc repair itself?

Answer 15

No, it is comprised of collagen, glycosaminoglycans, and elastin - but it is covered in fibrocartilage so that part can repair itself

Question 16

What muscle assists with closing?

Answer 16

Lateral ptyergoid

Question 17

What are the actions when opening the mouth?

Answer 17

Spin and then glide

Question 18

What are the two parts of the bilaminar retrodiscal pad?

Answer 18

Superior lamina and inferior lamina

Question 19

What is the function of the superior lamina?

Answer 19

Allows disc to translate anteriorly (opening)

Assist repositioning posteriorly (closing)

Question 20

What is the function of the inferior lamina?

Answer 20

Limits forward (anterior) translation

Question 21

What part of the lamina is stretched during dislocation?

Answer 21

Inferior lamina

Question 22

What are the three positions where the joint capsule is loose?

Answer 22

Anterior, medial, and posterior

Question 23

What is the main direction of dislocation?

Answer 23

Anteriorly

Question 24

How does the doctor have the move the jaw when it is dislocated?

Answer 24

Doctor has to distract the jaw down and push the jaw back into place

Question 25

Is the joint capsule innervated and vascularized?

Answer 25

Yes - aids in detailed info on movement and position

Question 26

What is the main ligament in the joint?

Answer 26

Temporomandibular ligament - runs superior to inferior

Question 27

What is the function of the temporomandibular joint?

Answer 27

Limits downward motion, posterior motion, and rotation during mandibular depression

Question 28

What are the five osteokinematic motions?

Answer 28

1. Mandibular depression 2. Elevation 3. Protrusion 4. Retrusion 5. Lateral excursion

Question 29

What are the four arthrokinematic motions?

Answer 29

Rolling, anterior glide, distraction, and lateral glide (not a lot of movement due to lateral joint capsule being strong)

Question 30

What is the normal ROM for depression?

Answer 30

40-50mm

Question 31

Describe rolling and gliding when opening the mouth.

Answer 31

Both anterior motions - rolling (spin) occurs between mandibular condyle and inferior disc and gliding occurs between superior disc and articular eminence (opposite when closing)

Question 32

What type of control occurs with the lateral ptyergoid?

Answer 32

Eccentric control of the disc when closing

Question 33

What limits protrusion?

Answer 33

Bilaminar retrodiscal tissue (superior lamina)

Question 34

What is protrusion important for?

Answer 34

Opening the mouth

Question 35

What is retrusion limited by?

Answer 35

Temporomandibular ligament and compression of the retrodiscal area

Question 36

What is retrusion important for?

Answer 36

Closing the mouth

Question 37

What is normal ROM for lateral excursion?

Answer 37

8-11mm

Question 38

What occurs during lateral excursion?

Answer 38

Ipsilateral condyle spins in transverse plane and contralateral condyle translates anteriorly - ex: left lateral excursion = left side spins and right side translates anteriorly

Question 39

What is deviation?

Answer 39

"S" curve - returns to midline

Question 40

What is deflection?

Answer 40

"C" curve - does not return to midline

Question 41

What is the function of the temporalis?

Answer 41

Closing, retrusion, and ipsilateral deviation

Question 42

What is the function of the masseter?

Answer 42

Closing and retrusion

Question 43

What is the function of lateral pterygoid?

Answer 43

Protrusion and contralateral deviation

Question 44

What is the function of the medial pterygoid?

Answer 44

Closing, protrusion, and contralateral deviation

Question 45

What are the suprahyoid muscles?

Answer 45

Digastric, geniohyoid, mylohyoid, and stylohyoid

Question 46

What is the function of the suprahyoid muscles?

Answer 46

Mandibular depression

Question 47

What are the infrahyoid muscles?

Answer 47

Omohyoid, sternohyoid, sternothyroid, and thyrohyoid

Question 48

What is the function of the infrahyoid muscles?

Answer 48

Stabilize the hyoid

Question 49

What is the resting position of the TMJ?

Answer 49

1.5-5mm opening (teeth are not touching) - TMJ stress is decreased

Question 50

What is the disadvantage of forward head posture?

Answer 50

Jaw retrudes which compresses the retrodiscal tissue, so the massication muscles have to overwork to close the jaw - infrahyoid muscles are put on stretch which pulls the hyoid posteriorly and causes retrusion

Question 51

Which lateral pterygoid is contracted with deviation to the left?

Answer 51

Right lateral pterygoid