5. TMJ Disorders II (intra-articular) Flashcards
What is the reference standard for the diagnosis of intracapsular TMD
MRI
What is the reference standard for the dx of pain-related TMD
clinical exam
MRI planes of view are
saggital and coronal
Disc displacements are defined in what view
saggital
Coronal view for an MRI is used to Dx what for TMD
medial/lateral disc displacement
Describe the normal position for the disc in an MRI
Observed from the sagittal plane
- Relative to the superior aspect of the condyle the boarder between the low and high signals of the disc is located between the 11:30 and 12:30 positions
- Intermediate zone is located between the anterior superior and the posterior inferior aspect of the articular eminance (AE)
- Disc is centered between the condyle and eminance in the medial, central and lateral parts
Describe Indeterminate disc placement
- High and low signal of the disc are located anterior to the 11:30 point but the intermediate zone is between the anterior superior and posterior inferior points on the AE
- Low and high signal of the disc are located between 11:30 and 12:30 but the intermediate zone is located anterior to the condyle
- Disc is centered between the eminance and condyle (no medial/lateral deviation)
Describe the location of the disc when it is displaced
- High and low signals of the disc are anterior to the 11:30 position
- The intermediate xone of the disc is anterior to the condyle
- Disc is not centered between the condyle and eminance (medial or lateral deviation)
Describe where the posterior band is located on an MRI
Where the dark and gray ends meet in the fossa
Make sure you look at the article pictures of the MRIs
Ok
If there are joint noises there is disc displacement (with/without) reduction
with
What does reduction mean in terms of joint displacement
it means that in the closed position the disc is displaced anteriorly and upon opening the position of the disc corrects and the intermediate zone is between the condyle and AE again
Describe disc displacement with reduction
-Intracapsular biomechanical disorder
-Closed position= disc is anterior relative to the condyle head
-Clicking, popping, snapping noises may occur
-History of prior locking in the closed position and interference with mastication precludes this dx
-
What historical, clinical, and imaging findings must be present to confirm a dx of DD with reduction
History
- Positive for at least one of the following
- Last 30 days- TMJ noises during movement or function
- Patient reports hearing TMJ noises during exam
Clinical
- Must have one of the following
- Noises both opening and closing or
- Noises with either opening or closing and noises during excursive and protrusive movements
Imaging
- Closed= Anterior displacement of the disc (posterior band anterior to 11:30 and intermediate zone anterior to condyle head)
- Open= Intermediate zone in between with condyle and AE
T/F Imaging is required to confirm a Dx of DD with reduction
T- poor validity (low sensitivity) otherwise
The intermediate zone is described as the (fat/skinny) part of the disc
skinny
In the open position for a patient with DD with reduction what does the MRI picture look like
condyle with a top hat on
What are the differences between DD with reduction and DD with reduction and intermittent locking
-Everything is the same except patient reports in their history that their jaw locks and prevents them from opening all the way