TMJ

Question 1

Bilateral diarthrosis

Answer 1

left and right sides function together

Question 2

Articulating surfaces are covered in

Answer 2

fibrocartilage

Question 3

Synovial

Answer 3

lined by synovial membrane

Question 4

ginglymoarthrodial joint

Answer 4

hinge and sliding movements

Question 5

Articular disc

Answer 5

● Composed of type 1 collagen and elastin
● Avascular
● Biconcave shape
● Divides the joint into two compartments

Question 6

upper joint space facilitates what movement

Answer 6

translational movements (protrusion and retrusion)

Question 7

lower joint space facilitates what movement

Answer 7

rotational movements (depression and elevation)

Question 8

Retrodiscal ligament

Answer 8

● Attaches the articular disc and condyle anteriorly and to the external auditory meatus and postglenoid spine posteriorly
● Superior retrodiscal lamina: prevents the disc from dislocating anteriorly
● Inferior retrodiscal lamina: prevents the disc from rotating over the condyle

Question 9

Synovial membrane

Answer 9

● Specialized endothelial cells that line the inner surface of the joint capsule
● Secretes synovial fluid which functions to minimize friction and distribute nutrients

Question 10

Bone

Answer 10

● Condylar head of the mandible
● Glenoid fossa and articular tubercle of the temporal bone

Question 11

Articular cartilage

Answer 11

● Lining of articular surfaces of the condyle and mandibular fossa
● Composed of type II collagen and proteoglycans

Question 12

major ligament

Answer 12

(intrinsic/functional)
○ Temporomandibular (lateral): limits mouth opening and prevents dislocation posteriorly

Question 13

minor ligaments

Answer 13

(extrinsic/accessory)
○ Stylomandibular: limits mandibular protrusion
○ Sphenomandibular: remnant of Meckel’s cartilage

Question 14

Neuro innervation of TMJ

Answer 14

Sensory innervation primarily by auriculotemporal nerve of CN V3

Question 15

Vasculature of TMJ

Answer 15

Blood supplied by the superficial temporal and maxillary arteries (branches of the external carotid artery)
○ Superficial temporal artery: supplies the retrodiscal tissue
○ Maxillary artery: supplies the anterior portion of the TMJ

Question 16

TMJ clicking

Answer 16

common finding in patients with disc displacement with reduction
● Clicking occurs when the disc slips anterior to the condyle upon opening and when it slips back into place upon closure

Question 17

Crepitus

Answer 17

crunching sound often associated with more advanced TMD
● Common in patients with arthritis
● Results from damage to the articular disc

Question 18

Locking

Answer 18

symptom in patients experiencing disc displacement without reduction
● Anterior displacement of the disc inhibits mouth opening (closed lock)
● Posterior displacement of disc inhibits closing (open lock)

Question 19

Deviation

Answer 19

upon opening, the jaw moves to one side and returns back to midline at maximum opening, often described as a “C” or “S” pattern

Question 20

Deflection

Answer 20

upon opening, the jaw moves to one side and does not return to the midline
● Direction of jaw movement is often related to a problem with the ipsilateral condyle