TMJ - Slides Flashcards
What type of joint is the TMJ?
synovial condylar ovoid
What is the benefit of the TMJ being lined with fibrocartilage?
more durable - strong/rigid which makes it optimal for tendunous insertion
The temporal bone articulates with the mandible via its… which articulates with the ____ of the mandible
GLENOID/MANDIBULAR FOSSA
MANDIBULAR CONDYLE
Which two muscles insert on the coronoid process?
temporalis and masseter
Which muscles depress the TMJ?
Suprahyoids & lateral pterygoid
The articular disc of the TMJ is aneural in the ____, whereas the ___ is vascular and neural
centre, periphery
The first 20mm of jaw opening only involves…
rotational movement of the condyle within the socket
For the mouth to open more than 20mm, the disc has to move forward and down the ____ - this movement is called ____
articular eminence
translation
Why is anterior disc displacement of the TMJ painful?
when the disc is pulled too far forward, the retrodiscal tissue (which is pain sensitive) gets compressed by the condyle while the disc gets stuck anteriorly
What likely occurs when the jaw locks?
The articular disc is stuck anteriorly; the retrodiscal tissue is compressed in the glenoid fossa by the mandibular condyle. When the person tries to open their jaw again, the anteriorly displaced disc prevents the condyle from being able to move forward
What is a “pseudo disc”?
when the retrodiscal tissue becomes scar tissue and can functionally replace the disc!
What does a C-curve suggest? Which direction does a REVERSE C-curve deviate?
C curve = capsular restriction, hypomobility on the side of deviation
Reverse c-curve = to the right
What does an S curve suggest? An S-curve will go which direction first?
suggests muscle imbalance
S curve will go to the left, THEN to the right
With an S curve, the chin will deviate to the affected/unaffected side first?
affected
Which lateral pterygoid head attaches to the articular disc and capsule?
superior
The lateral pterygoid heads originate on what bones and insert on what bones?
originate from sphenoid
insert on mandible and articular disc
The temporomandibular ligament checks which excess movements?
forward, backward, and lateral
The sphenomandibular ligament checks which movements?
it’s a suspensory ligament during wide mandibular openings
When the mouth is open wide, what will the state of the temporomandibular and sphenomandibular ligaments be?
temporomandibular ligament slackens, sphenomandibular ligament becomes taught (as a suspensory ligament)
The stylomandibular ligament separates the __ and __ muscles
masseter, medial pterygoid
Which nerves innervate the TMJ?
auriculotemporal and masseteric branches of the mandibular nerve
Gliding/sliding/translation movements occur in which part of the TMJ?
upper cavity
Rotation/hinge movement occurs in which part of the TMJ?
lower cavity
What is centric occlusion?
maximum contact of teeth (when you bite together)
What is median occlusion?
the position where the teeth are fully interdigitated
What does early clicking suggest?
a developing dysfunction
What does late clicking suggest?
more likely a chronic problem
Soft or popping clicks are caused by…
ligamentous movement, articular surface separation, sucking of loose tissue d/t muscle incoordination
Hard crepitus or hard/cracking clicks are more likely to indicate…
pathology or joint surface defects
Describe “reciprocal clicking”
early click on opening, late click on closing
What occurs in phase 1 of mouth opening?
rotation
What occurs in phase 2 of mouth opening?
translation and rotation
When does phase 2 of mouth opening begin?
when tongue loses contact with roof of mouth
If clicking occurring upon opening the jaw is eliminated by opening with the jaw protruded, and accentuated with retrusion, it is likely…
anterior disc displacement with reduction
The thickest portion of the TMJ disc is the ___ band, and the thinnest is the ___ zone
posterior
intermediate zone
With HFP, muscles like ___ and ___ are in some level of continuous tension
longus capitis and longus colli
How does HFP affect the suprahyoids?
they are shortened d/t need to hyperextend the head to maintain ability to look ahead
Which spinal segment can see compression with HFP?
C1-C2
What are the 4 stages of TMJ syndrome?
- early incoordination (usually reversible but can result in degenerative changes)
- limitation phase (irreversible degeneration)
What percentage of the population as TMJS?
20%
Pain in fully opened position is likely a ____ problem.
Pain with biting firm objects is likely a _____ problem.
extra-articular
intra-articular
What are the 3 cardinal S&S of TMJS?
- pain in TMJ affected by movement
- joint noise during movement
- restrictions/limitations during jaw movement
On opening, the later a click occurs, the more ___
the more anteriorly the disc is displaced
If the closing click occurs near the end of the closing pathway, it is likely d/t…
pull of the lateral pterygoid
CLICKING is clinical evidence that:
This is more likely to occur in ___ joints.
the condyle is slipping over the disc and then self-reducing
hypermobile
Crepitus in the TMJ suggests that…
there is DJD , perforation in the disc, that bone is rubbing together
What is an adhesive click? Who does it appear in?
after periods of clenching - adhesions in superior/inferior limit translation or rotation, causing a temporary closed lock - then opens with a click
If the jaw will not open from closed position, it is likely the disc is…
posterior or anteromedial to the condyle
If the jaw will not close from opening, the disc or joint is likely…
There will likely be what clicking behaviour?
posteriorly displaced, or the joint subluxed
2 clicks on opening: 1 as the condyle moves over posterior rim, then when it moves over anterior rim.
Functional dislocation with reduction will c/o:
occasional locking and limited opening, the jaw ‘catches’
Functional dislocation without reduction will c/o:
closed lock, mandible deviates to affected side
With the TMJ, you should always assess ___ first.
aROM of C/s
