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
What is the name for open lock
subluxation
Describe DD without reduction with limited opening history, clinical and imagining findings
History
- Jaw locking so mouth wouldn’t open all the way
- Limitation in jaw opening severe enough to limit ability to eat
Clinical
-MOA <40 mm
Imaging
- Closed= anteriorly displaced disc
- Open= Anteriorly displaced disc
**Presence of TMJ sounds doesn’t exclude this Dx
Closed position for MRI is taken in what jaw position
MIP
What patients are candidates for surgery
closed lock
Describe the historic. clinical, and image findings for DD without reduction without limited opening
History
- Positive for both
- Jaw locked so that the mouth wouldn’t open all the way
- Limitation in jaw opening interfering with ability to eat
Clinical
-MOA <40 mm
Imaging
- Closed= anteriorly displaced disc
- Open= Anteriorly displaced disc
Presence of TMJ noises doesn’t exclude this Dx
What other measurement do you need to consider when obtaining MAO
vertical overlap
Which of the following disc displacement diagnosies provides the best validity based on sesnitivity and specificity
DD without reduction with limited opening
What imaging is needed for a dx of Degenerative joint disease (DJD)
CT
What are the planes of view in a CT
axial and coronal (can be manipulated into a sagittal view as well)
Describe a normal condyle appearance in CT
- Normal relative size (although size does vary)
- Defined cortical margin
- No subcortical sclerosis or articular surface flattening
- No deformation due to subcortical cyst, surface erosion, osteophytes, or generalized sclerosis
T/F Marginal sclerosis and Condyle flattening are a part of DJD diagnosis
F
Describe the historical, clinical, and imaging findings needed for a DJD diagnosis
History
-Last 30- report TMJ sounds from jaw movement or function or reports hearing them during the exam
Clinical
-Crepitus detected with palpation during open/close/lateral/protrusive movements
Imaging
- At least one of the following is present
- Subchondral cyst, erosion, generalized sclerosis, or osteophytes
- Not marginal (localized) sclerosis) or flattening of the condyle
Why are marginal sclerosis and flattening not part of DJD dx
these may represent normal variation, aging, remodeling, or a precursor to frank DJD
Describe the historic, clinical, and imaging findings with subluxation
History
- Positive for both
- Last 30 days jaw locking or catching in a wide open mouth position
- Inability to close the mouth from a wide open position without a self-maneuver
Imaging
-Condyle positioned beyond the height of the articular eminance with patient unable to close mouth without a maneuver
Give two examples of hypomobility disorders
- Intra-articular fibrous adhesions
- Ankyloses
Hypomobility disorders are often a sequalae of
trauma
hypomobility disorders typically (are/aren’t) associated with pain
aren’t
Most frequent cause of TMJ ankylosis is _ and less frequently caused by _
Most= macrotrauma Less= infection of the mastoid or middle ear, systemic disease and inadequate surgical treatment of condyle area
Hypomobility disorders are characterized by
- Restricted mandibular movement
- Deflection to the affected side on opening
Associated characteristics of of hypomobility disorders are
- History of loss of jaw mobility
- Positive diagnosis of a disc-complex disorder
- Limited range of motion on opening
- Marked deflection to the affected side
- Markedly limited laterotrusion to the contralateral side
Fibrous adhesions in the TMJ most often occur where
Superior compartment
Radiographic findings of fibrous ankylosis
none other than absence of ipsilateral condylar translation on opening
Radiographic findings of osseous ankylosis
- Bone proliferation
- Marked deflection to affected side
- Limited laterotrusion to the contralateral side
Which is more common osseous or fibrous ankylosis
fibrous
What is required to confirm a Dx of fibrous ankylosis
- History of progressive loss of jaw mobility
- Limited range of motion on opening
- Marked deflection to the affected side
- Markedly limited laterotrusion to the contralateral side
Imaging must also show…
- Decreased to complete lack of ipsilateral condylar translation on opening
- A disc space between the ipsilateral condyle and the eminence
Define aplasia
-(typically unilateral) absence of the condyle
0Incomplete development of the articular fossa and eminance
-Results in facial asymmetries
Define hypo and hyperplasia
Under/over development of the cranial bones or mandible. (hyperplasia= non-neoplastic)
People with Rheumatoid arthritis typically have (anterior/posterior) (open/closed) bites and why
Anterior open because the joint degenerates causing the condyles (or the ramus?) to shorten. Then when the elevator muscles contract the condyles pivot leading to open bite
Review cases and articles
ok
