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Statement of Problem: Trajectories of different condylar points provide different interpretations of condylar movement during open-close jaw movements. Movement of the working-side condyle is often assessed clinically by recording the trajectory of a single arbitrary condylar point., Purpose: This study examined the effect of the differences in condylar point location on condylar point movement trajectories during a working-side movement., Methods: Different points exhibited different trajectories during a single working-side movement in each of 44 subjects., Results: Up to 40% of a point's displacement could be attributed simply to the location of the point., Conclusions: Interpretation of condylar movement on the working side within a subject depends on the point chosen.

Two imaging methods are useful in diagnosing internal derangements of the temporomandibular joint: arthrography and magnetic resonance imaging (MRI). Clinical and pseudodynamic MRI findings of 200 temporomandibular joints in 100 patients were evaluated and compared. In 66.5% of the joints, there was a positive correlation between both diagnostic methods. MRI showed the possibility to correct the clinical diagnosis in more than half of the remaining joints. The other half of the joints are a source of discussion and suggest that MRI has some difficulties in detecting the exact disk position, especially in joints with an anterior disk displacement with early reduction. MRI revealed degenerative changes in 43.5% of the joints. They were often seen in joints with a disk displacement without reduction, even in young patients. Pseudodynamic MRI is especially useful in the differential diagnosis of a "closed lock" and should certainly be done when disk surgery is planned.