TMJ

Question 1

how much of the population has atleast 1 type of orofacial pain in past 6 m

Answer 1

22% in last 6 months

Question 2

4 actions of the TMJ

Answer 2

1. Protrusion
2. Retraction
3. Elevation
4. Depression

Question 3

muscles that protrusion and retraction

Answer 3

pro- lat pterygoid (assisted by medial pterygoid)

Ret- Post fibres of temporalis

Question 4

muscles that elevate and depress the mandible

Answer 4

elevate- temporalis, massater, medial pterygoid

Depress- geniohyoid+ mylohyoid m

Question 5

surface of the TMJ is what and what are the advantages

Answer 5

Fibrocartilaginous surface (not hyaline)

• Less susceptible to aging + breaking down
• better ability to repair
• has a disk to seperatr the jt into sup and inf

Question 6

2 functions of the TMj and where does it occur in the jt

Answer 6

1. Rot- in inf cavity

2. Translation- in sup cavity

Question 7

how does rot start at the tmj

Answer 7

• rot occurs from the begining to midrange of jaw oppening

- lat pterygoid muscle draws the disk ant

Question 8

what two ligs act as restraints to keep condyle,disk and temporal bone fimly opposed

Answer 8

Stylomandibular + sphenomandibular ;ligs

Question 9

what are the retrodiscal tissues and what are their sig

Answer 9

post to tmj, highly sensitive and can get impiged i the pterygoid fails to pull jaw forward

Question 10

what are the steps of mandibular depression

Answer 10

1. rot- starts w contraction of lat pterygoid + suprahyid m, which rot the condyle (first 20)
2. translation- lat pterygoid pulls condyle forward
3. on full opening post temporalis contract to fully open jaw

Question 11

what muscles are primarily responsible for mandibular closure and bite

Answer 11

Messeter, medial pterygoid, temporalis

Question 12

averge opening of mouth

Answer 12

40-60mm (9% can fit 4 fingers)

Question 13

What limits rotational opening

Answer 13

outer oblique portion of the tempomandibular lig

Question 14

what is lock jaw

Answer 14

forward subluxation of tmj

Question 15

biting hard on one side increases the forces on what side and what muscle prevents dislocation

Answer 15

increases pressure on contralat side and decreases it ipsilat

• can dislocate the ipsilat tmj
• sup lat pterygoid prevents this

Question 16

mechanism of early tmj click

Answer 16

1. slight already ant disc displacement (stops condyles from moving)
2. extra force moves condyles enough to ride over post apect of disk `
3. as they close the condyle rides back over post disck causing click

Question 17

what happens in tmj blocking

Answer 17

(NO CLICK)
condyle is stuck behind disk
blocks translation and thus mouth from being able to open

Question 18

if lock is in open or closed pos what does it indicate

Answer 18

close- closed lock (disk forward)

Open- prob due to sublux of the jt ant to eminence

Question 19

tx of tmj jt disorders

Answer 19

• reassurance
• physical therapy
• massage
• manual mobalization
• surgery

Question 20

how do you qualify a tmj disrder

Answer 20

if mandible protrudes an intial phase of opening

Question 21

what is the underlying dysfunction that causes tmj disorders

Answer 21

Overactivation of elevation mm and inhibition of depression m
(lat pterygoid dominates + produces early protrusion)