As described, CT is a noninvasive method for providing detailed views of both the soft and hard tissues of the TMJ region. Because internal derangements of the joint involve both of these structures, CT can provide an invaluable tool in the study, diagnosis, and treatment of various disorders of this nature. It is extremely important, however, to create a close working relationship with the radiologist who will be performing these studies. Only with adequate clinical study and information communicated to the radiologist can true benefits be obtained. As CT scans are available nationwide, this technique should be available to nearly any practitioner in the country. CT can be useful in both diagnostic and therapeutic modalities. On a diagnostic basis, it can provide a tomographic study of the osseous structures of the condyle, fossa, articular eminence, and surrounding hard tissues. By varying the slices, views of the medial and lateral poles as well as the central portions of the region, can be obtained. In this way, various arthroses, tumors, cysts, fractures, true ankylosis, neoplasias, developmental abnormalities, and other bony abnormalities can be clearly found. Therapeutically, CT can evaluate the success of treatment aimed at reestablishing proper disk-condylar relationships. However, the major advantage of TMJ CT is the observation of the soft tissue of the articular disk. By the use of CT, especially enhanced by the blink mode, we can see how the disk relates to the condyle. If a series of views are taken in both the closed and open position, we can observe the disk-condylar relationship during this range of motion.(ABSTRACT TRUNCATED AT 250 WORDS)