Temporomandibular Joint (TMJ)

The temporomandibular joint (TMJ) is the joint that connects the lower jaw (mandible) to the temporal bone of the skull, just in front of each ear. There is one on each side, and they work together every time you open your mouth, chew or speak. "TMJ" is also used informally for jaw joint problems, which clinicians call temporomandibular disorders (TMD).

Why It Matters

The two joints and the chewing muscles work as a single system, so a problem in one part can cause pain in the jaw, face, temples or around the ear, headaches, clicking, or difficulty opening the mouth. Many of these symptoms come from the muscles rather than the joint itself and improve with simple, reversible care. Because jaw pain can also come from the teeth or sinuses, an accurate diagnosis matters before treatment.

Clinical Details

Anatomy: The rounded head of the lower jaw (condyle) sits in a socket in the temporal bone, with a cartilage disc between them. The joint both hinges and glides forward, which allows wide opening and side-to-side movement.
Common problems: Muscle pain in the jaw and temples, displacement of the disc (often heard as clicking and occasionally causing the jaw to lock), and degenerative or inflammatory joint conditions.
Contributing factors: Clenching or teeth grinding, jaw injury, stress and some general joint conditions. The role of the bite is debated and is assessed case by case.
Assessment: History and examination of jaw movement, joint sounds and muscle tenderness. Imaging such as a panoramic X-ray, CBCT or MRI is used only when the findings call for it.
Management: Usually starts with self-care (soft diet, avoiding gum chewing and very wide opening), heat or cold, pain relief, jaw exercises and, where appropriate, a custom night guard (occlusal splint). Irreversible treatments are reserved for specific cases.

FAQ

What is the difference between TMJ and TMD?

TMJ is the name of the jaw joint itself. TMD is the group of conditions that cause pain or dysfunction in that joint and the surrounding chewing muscles.

Is jaw clicking a problem?

Clicking without pain or locking is common and often needs no treatment. See a dentist if clicking comes with pain, the jaw locks open or closed, or opening becomes limited.