Temporomandibular Joint Disorder
(TMJ)

Medical Author: William C. Shiel Jr., MD, FACP, FACR

• What is the temporomandibular joint?
• What are TMJ disorders, and how are they caused?
• What are the common symptoms of TMJ disorders?
• How are patients evaluated when TMJ problems are suspected?
• How can TMJ be treated?
• Temporomandibular Joint Disorder At A Glance

What is the temporomandibular joint?

The temporomandibular joint (TMJ) is the area directly in front of the ear on either side of the head where the upper jaw (maxilla) and lower jaw (mandible) meet. Within the TMJ, there are moving parts that allow the upper jaw to close on the lower jaw. This joint is a typical sliding "ball and socket" which has a disc sandwiched between it. The TMJ is used many hundreds of times a day in moving the jaw, biting and chewing, talking and yawning. It is one of the most frequently used of all the joints in the body.

The temporomandibular joints are complex and are composed of muscles, tendons, and bones. Each component contributes to the smooth operation of the TMJ. When the muscles are relaxed and balanced and both jaw joints open and close comfortably, we are able to talk, chew, or yawn without pain.

We can locate the TMJ by putting a finger on the triangular structure in front of the ear. The finger is moved just slightly forward and pressed firmly while opening the jaw. The motion felt is from the TMJ. We can also feel the joint motion if we put a little finger against the inside front part of the ear canal. These maneuvers can cause considerable discomfort to a patient who is experiencing TMJ difficulty, and doctors use them for making the diagnosis.

What are TMJ disorders, and how are they caused?

TMJ disorders are a group of complex problems related to the jaw joint. Other names include myofacial pain dysfunction and Costen's syndrome. Because muscles and joints work together, a problem with either one can lead to stiffness, headaches, ear pain, bite problems (malocclusion), clicking sounds, or locked jaws. The following are behaviors or conditions that can lead to TMJ disorders.

1. Teeth grinding and teeth clenching (bruxism) increase the wear on the cartilage lining of the TMJ. Patients may be unaware of this behavior unless they are told by someone observing this pattern while sleeping or by a dental professional noticing telltale signs of wear and tear on the teeth. Many patients awaken in the morning with jaw or ear pain.



2. Habitual gum chewing or fingernail biting.



3. Dental problems and misalignment of the teeth (malocclusion). Patients may complain that it is difficult to find a comfortable bite or that the way their teeth fit together has changed. Chewing on only one side of the jaw can lead to or be a result of TMJ problems.



4. Trauma to the jaws. Previous history of broken jaw or fractured facial bones.



5. Stress frequently leads to unreleased nervous energy. It is very common for people under stress to release this nervous energy by either consciously or unconsciously grinding and clenching their teeth.



6. Occupational tasks such as holding the telephone between the head and shoulder.

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