MR Imaging of the TMJ: A Pictorial Essay

Chris Roth, MD; Robert J. Ward, MD; Scott Tsai, MD; Wendy Zolotor, MD; Richard Tello, MD, MSME, MPH

Disclosures

Appl Radiol. 2005;34(5):9-16. 

In This Article

Dislocation

Dislocation of the TMJ usually occurs anteriorly. Displacement posteriorly, superiorly, or medially is prohibited by the contour of the ipsilateral glenoid fossa. Laterial displacement is prevented, as the medial wall of the contralateral glenoid fossa confines the contralateral condyle. A dislocation in any direction except anterior implies a fracture of either the articular fossa or the mandible.

An anteriorly dislocated mandibular condyle is visualized anterior and superior to the articular eminence (Figure 9). A patient with a dislocated mandible is unable to close his or her mouth. Conversely, in subluxation, the condyle reduces in the closed-mouth position.[2] Other stigmata of traumatic injury can be readily appreciated on MR images of the TMJ, such as fractures, bone marrow edema, and hemarthroses.

A 27-year-old man with a dislocated right tempomandibular joint. Sagittal T1-weighted image shows the dislocated mandibular condyle (black arrow) anterior to the articular eminence (white arrow) and an empty glenoid fossa (black arrowhead). The disk is folded below the articular eminence.

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