FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

MIXED-UP BRAIN INTERPRETS PAIN SIGNALS FROM JAW AS EARACHE

Question: My ear was painful for several weeks. My doctor finally diagnosed the problem as TMJ pain. How does TMJ cause ear pain?

Answer: TMJ stands for temporomandibular joint, which is more commonly known as the "jaw joint." There is no other joint in the body quite like it. The mandible, or jawbone, doesn't simply fit into a joint socket but instead rests on an "articular disk" that is located between the end of the jawbone and skull. This construction allows the mouth to open very wide and also makes it possible to produce the forward gliding and side-to-side wiggle motions necessary for chewing.

When we chew or engage in other biting actions, the TMJ is subjected to considerable physical stress. We all know how hard fingernails can be, yet it is common to see individuals bite off their nails. The powerful force produced by the muscles of the jaw (also called muscles of mastication) pull on the teeth and the jaw joint. Even though well designed to handle the usual forces placed upon it, the TMJ can be injured by overuse or trauma. When injured, the TMJ signals the brain of this undesirable condition in a way that we recognize as pain.

The brain, however, sometimes has trouble interpreting the source of the pain signals accurately. For instance, as in your case, the brain may interpret the pain as coming from the ear, a part of the body also innervated by the trigeminal nerve. This is the same phenomenon that occurs when you knock your "funny bone" against a table or other hard object. Although you've bumped your elbow, the sensation affects the entire area served by the mildly traumatized ulnar nerve. That's why your whole arm feels "funny."

Temporomandibular joint disorders, including pain, popping noises, limited "range of motion" and locking, afflict as many as 30 to 50 percent of the U.S. population. Most problems are mild and don't require the attention of a doctor, dentist or orthodontist. Almost 5 percent of the population have more significant trouble that causes the person to seek the attention of one or more of these health-care professionals. Women in their reproductive years are troubled with these maladies five times more often than are males or other groups of females.

TMJ pain is usually the consequence of chronic strain and injury to the muscles of mastication and to the joint structures. Rarely is it due to arthritis, broken bones, tumors, or life-threatening conditions. Treatment is, therefore, conservative in nature. Education about the condition, jaw rest, specific exercises, pain medication and occasional use of an appliance such as a "bite block" are common treatment options. One of these treatments alone, or in combination with others, is usually successful in eliminating the pain. If the cause of the pain is teeth grinding or clenching, counseling may be necessary to deal with underlying issues that cause this activity in the first place. Only in rare situations is surgery necessary.

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701.