How it’s done

TMJ MRI images the joint in both closed- and open-mouth positions, usually both sides. The articular disc, normally sitting like a bow-tie over the condyle, is tracked as the mouth opens. Fluid-sensitive sequences add effusion and marrow information.

Disc displacement patterns

• Displacement with reduction: disc is anteriorly displaced in closed mouth but recaptures on opening (the classic clicking joint).
• Displacement without reduction: disc stays displaced on opening (associated with restricted opening/locking).
• Direction: most commonly anterior, sometimes anteromedial/lateral.

Other findings

MRI also shows joint effusion (often with pain), degenerative change (condylar flattening, osteophytes, marrow oedema), and disc deformity. Findings are interpreted with symptoms. Asymptomatic disc displacement exists, so imaging supports rather than replaces clinical assessment.