Temporomandibular joint

The temporomandibular joint is the joint of the jaw and is frequently referred to as TMJ. There are two TMJs, one on each side, working in unison. The name is derived from the two bones which form the joint: the upper temporal bone which is part of the cranium, and the lower jaw bone called the mandible. The unique feature of the TMJs is the articular disc.

Temporomandibular joint pain is generally due to one of four reasons.

• Myofascial pain dysfunction syndrome, primarily involving the muscles of mastication. This is the most common cause.
• Internal derangements, an abnormal relationship of the disc to any of the other components of the joint. Disc displacement is an example of internal derangement.
• Osteoarthritis of the temporomandibular joint, a degenerative joint disease of the articular surfaces.
• Temporal arteritis, for which it is considered a reliable diagnostic criteria

Pain or dysfunction of the temporomandibular joint (TMJ) is sometimes referred to as temporomandibular joint dysfunction or temporomandibular joint disorder (TMD). This term is used to refer to a group of problems involving the temporomandibular joints and the muscles, tendons, ligaments, blood vessels, and other tissues associated with them.

Although rare, other pathologic conditions may also affect the function of temporomandibular joints, causing pain and swelling. These conditions include chondrosarcoma, osteosarcoma, giant cell tumor, and aneurysmal bone cyst.