Cross-sectional and functional imaging of the temporomandibular joint: radiology, pathology, and basic biomechanics of the jaw.

The temporomandibular joint (TMJ) is a common site of complaint. Clicking sounds and pain are indicators of a frequent condition called internal derangement, most often affecting females. As a general term, internal derangement describes a structural abnormality within an articulation. The internal derangement of the TMJ is a specific term defined as an abnormal positional and functional relationship between the disk and articulating surfaces. Imaging of the joint is an important element in the diagnostic work-up. Trauma and inflammatory arthritis account for most of the other TMJ problems. A thorough understanding of joint anatomy and normal function is a prerequisite for perceiving abnormalities and making the correct diagnosis. The authors elucidate joint anatomy, correlating cadaveric specimen and anatomic slices with conventional and cross-sectional imaging studies. TMJ biomechanics are illustrated with schematics and animations, and an overview of imaging strategies and techniques is presented. Common abnormalities are described and illustrated, and a brief discussion of therapeutic options is included.