A variety of conditions affecting the anatomic and functional characteristics of the temporomandibular joint. factors contributing to the complexity of temporomandibular diseases are its relation to dentition and mastication and the symptomatic effects in other areas which account for referred pain to the joint and the difficulties in applying traditional diagnostic procedures to temporomandibular joint pathology where tissue is rarely obtained and x-rays are often inadequate or nonspecific. common diseases are developmental abnormalities, trauma, subluxation, luxation, arthritis, and neoplasia. (from thoma's oral pathology, 6th ed, pp577-600)