Table 1.

Staging criteria for the MRI parameters according to Moen et al. (15).

Disc position	Anterior disc position was defined as the end of the posterior band located anterior to the 10 o’clock position relative to the condyle (16). Anterior dislocation (Figs. 1 and 2) was registered according to Drace and Enzmann (17). Only disc displacement in sagittal direction was described.
Disc deformation	Registered as pathologic when the biconcave morphology of the disc was clearly changed.
Effusion	Fluid in the synovial compartments (Fig. 2) was, when clearly apparent, registered in three different grades: moderate, marked, or extensive according to Larheim and Westesson (18).
Caput flattening	Obvious flattening only was registered as pathological (Fig. 3).
Surface destructions	Obvious or extensive destructions on the surface of the condylar head were registered as pathological (Fig. 3).
Osteophytes	Registered as present or not (Fig. 1).
Caput edema	Bone marrow edema in the condylar head was registered by hypo intensive signal on T1 and hyper intensive on T2-weighted images, according to Larheim et al. (19).

MRI, magnetic resonance imaging.