Function of Temporomandibular Joint: Normal / Abnormal

All of us are born with a natural cushion built into most of the joints in our body for the purpose of absorbing shock. This cushion called a disc, has different characteristics in different joints but, when injured, can be a source of mechanical failure in all joints. The temporomandibular joint (TMJ) is no different in that respect and is even more complex than most other human joints. Through an act of Mother Nature we are capable of virtually unhinging the joint at its usual point of rest in order to move our jaws from side to side or to affect a wider opening. This complex movement during function necessitates a harmonious move by the disc to maintain its protective position.

Unfortunately, it is not infrequent that this disc can become damaged or displaced. As the disc is damaged or slips from its original position, the individual may experience clicking in the joint as well as joint locking, as the disc malfunctions and becomes an obstruction to normal joint movements. This condition often becomes painful due to sensitive tissues becoming inflamed and swollen. Moreover, nerves associated with these tissues are capable of referring pain to areas away from the original site of the injury resulting in symptoms such as earaches and headaches.

Function of Jaw Muscles

The jaw muscles (muscles of mastication) attach to the lower jaw (mandible), upper jaw (maxilla), skull and neck. The muscles of mastication open and close, protrude, and laterally move the jaw, enabling you to talk, chew, and swallow. The supporting muscles of mastication (neck and shoulder girdle muscles) stabilize the skull on the neck during jaw function.