Patients displaying temporomandibular joint clicking or with a history of clicking followed by limitation of opening were subjected to clinical and radiological examinations including arthrography. Arthrotomographically the patients were found to have anterior displacement of the disc. In patients with clicking the disc was repositioned in association with clicking during opening. In patients with limitation of opening the disc was constantly displaced anterior to the condyle, blocking anterior condylar translation. The patients with limitation of opening had more pain, more signs of mandibular dysfunction, more hard tissue changes and more frequent perforation and deformation of the disc, compared to patients with clicking only. These findings may justify two different diagnoses, displacement with and without repositioning of the disc on opening. Displacement without repositioning seems to be the more advanced condition and may in some cases be a precursor of osteoarthrosis.