When You Have Temporomandibular Disorder (TMD)

The temporomandibular joint (TMJ)�is a ball-and-socket joint located where the upper and lower jaws meet. The TMJ and its nearby muscles make up a complex, loosely connected system. Because of this, a problem in one part of the system can affect the other parts. This can cause you to have temporomandibular disorder (TMD).

�

How the Temporomandibular Joint Works

You have one joint on each side of your mouth that together make up the TMJ. These joints are part of a large group of muscles, ligaments, and bones that work together as a system. When the system is healthy, you can talk, chew, and even yawn in comfort. Muscles contract and relax to open and close the joint. The disk absorbs pressure in the joint. It also allows the jaws to open and close smoothly. Ligaments connect the jaw bones to the skull. They also support the joint.

Common Temporomandibular Problems

When there is a problem with the TMJ and its related system, you can develop TMD. Common TMD problems include tight muscles, inflamed joints, and damaged joints.

In some cases, symptoms may be related to the teeth or bite.

• Tight muscles:�The muscles surrounding the TMJ can go into spasm (tighten) and cause pain. Referred pain occurs in a part of the body separate from the source of the problem. For example, pain in the face or teeth could be coming from a problem in the TMJ. Myofascial pain occurs in soft tissues, such as muscle. Trigger points in these pain areas often cause referred pain. You may feel jaw, neck, or shoulder pain.

• Inflamed joints: Inflammation�may include pain, redness, heat, swelling, or loss of function. Synovitis occurs when certain tissues surrounding the TMJ become inflamed. It causes pain that increases with jaw movement. Inflamed ligaments can be caused by strain or injury. When this happens, the ligaments are unable to support the joint. Rheumatoid arthritis is a joint disease. It leads to inflammation in the TMJ.

• Damaged joints:�Many people hear clicking when their jaw moves. If you feel pain along with the noise, the joint may be damaged. Impingement occurs when the disk slips out of place (displacement). This causes the jaw to catch. As the disk slips, you may hear a clicking sound. Locked jaw occurs when the disk gets stuck in one position. As a result, the jaw locks open or closed. Osteoarthritis is a joint disease. It causes the TMJ to wear away (degenerate). This leads to pain during movement.