In its 1996 consensus statement, the National Institutes of Health Consensus Development Conference defined temporomandibular disorders as follows: Temporomandibular disorders (TMD) refer to a collection of medical and dental conditions affecting the temporomandibular joint (TMJ) and/or the muscles of mastication, as well as contiguous tissue components. Although specific etiologies such as degenerative arthritis and trauma underlie some TMD, as a group these conditions have no common cause or biological explanation and comprise a group of health problems whose signs and symptoms are overlapping, but not necessarily identical.(1) In simpler terms, it is a condition which causes pain in the jaw muscle and has received a lot of attention as a cause of chronic headaches.

Although severe cases may require dental or oral surgery, most TMJ dysfunction is psychophysiologic in origin, or rather the result of nighttime jaw clenching and teeth grinding. This tension-relieving oral habit develops in response to situational and intrapsychic stresses and can lead to masticatory muscle fatigue and spasm.(2)

In the mainstream medical community, there is still a bit of confusion over the symptoms that can be classified and used in developing guidelines for diagnosis. So far there is a full range of symptoms from mild and hardly noticeable to severe. Often there are other diagnoses which describe symptoms of conditions such as arthritis, chronic dislocation, and growth disorders.