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Flashcards in TMJ Deck (21)
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how much of the population has atleast 1 type of orofacial pain in past 6 m

22% in last 6 months


4 actions of the TMJ

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


muscles that protrusion and retraction

pro- lat pterygoid (assisted by medial pterygoid)

Ret- Post fibres of temporalis


muscles that elevate and depress the mandible

elevate- temporalis, massater, medial pterygoid

Depress- geniohyoid+ mylohyoid m


surface of the TMJ is what and what are the advantages

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


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

1. Rot- in inf cavity
2. Translation- in sup cavity


how does rot start at the tmj

-rot occurs from the begining to midrange of jaw oppening
-lat pterygoid muscle draws the disk ant


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

Stylomandibular + sphenomandibular ;ligs


what are the retrodiscal tissues and what are their sig

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


what are the steps of mandibular depression

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


what muscles are primarily responsible for mandibular closure and bite

Messeter, medial pterygoid, temporalis


averge opening of mouth

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


What limits rotational opening

outer oblique portion of the tempomandibular lig


what is lock jaw

forward subluxation of tmj


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

increases pressure on contralat side and decreases it ipsilat

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


mechanism of early tmj click

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


what happens in tmj blocking

condyle is stuck behind disk
blocks translation and thus mouth from being able to open


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

close- closed lock (disk forward)
Open- prob due to sublux of the jt ant to eminence


tx of tmj jt disorders

-physical therapy
-manual mobalization


how do you qualify a tmj disrder

if mandible protrudes an intial phase of opening


what is the underlying dysfunction that causes tmj disorders

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