Temporomandibular Joint Syndrome

Definition

Temporomandibular joint syndrome (TMJ) is the name given to a group of symptoms that cause pain in the head, face, and jaw. The symptoms include headaches, soreness in the chewing muscles, and clicking or stiffness of the joints.

Description

TMJ syndrome, which is also sometimes called TMJ disorder, results from pressure on the facial nerves due to muscle tension or abnormalities of the bones in the area of the hinge joint between the lower jaw and the temporal bone. This hinge joint is called the temporomandibular joint. There are two temporomandibular joints, one on each side of the skull just in front of the ear. The temporal bone is the name of the section of the skull bones where the jawbone (the mandible) is connected. The jawbone is held in place by a combination of ligaments, tendons, and muscles. The temporomandibular joint also contains a piece of cartilage called a disc, which keeps the temporal bone and the jawbone from rubbing against each other. The jaw pivots at the joint area in front of the ear. The pivoting motion of the jaw is complicated because it can move downward and from side to side as well as forward. Anything that causes a change in shape or functioning of the temporomandibular joint will cause pain and other symptoms.

Causes & symptoms

TMJ syndrome has several possible physical causes:

• Muscle tension. Muscle tightness in the temporomandibular joint usually results from overuse of muscles. This overuse in turn is often associated with psychological stress and clenching or grinding of the teeth (bruxism).
• Injury. A direct blow to the jaw or the side of the head can result in bone fracture, soft tissue bruising, or a dislocation of the temporomandibular joint itself.
• Arthritis. Both osteoarthritis and rheumatoid arthritis can cause TMJ.
• Internal derangement. Internal derangement is a condition in which the cartilage disk lies in front of its proper position. In most cases of internal derangement, the disc moves in and out of its correct location, making a clicking or popping noise as it moves. In a few cases, the disc is permanently out of position, and the patient's range of motion in the jaw is limited.
• Hypermobility. Hypermobility is a condition in which the ligaments that hold the jaw in place are too loose and the jaw tends to slip out of its socket.
• Birth abnormalities. These are the least frequent causes of TMJ but do occur in a minority of patients. In some cases, the top of the jawbone is too small; in others, the top of the jawbone outgrows the lower part.
• Oral habits. Some dentists think that such habits as wide yawning, lip or tongue biting, or mouth breathing can contribute to TMJ by putting the jaw in an abnorml position for long periods of time.
• Dental work. Some people develop TMJ following dental work that requires the dentist to hold the patient's jaw open wide for extended periods of time. Other patients develop TMJ following removal of the wisdom teeth.

In addition to the physical causes of TMJ, dentists are increasingly recognizing the importance of psychosocial factors in the disorder. One recent finding is the importance of the patient's concept of pain itself. People who are already suffering from depression or an anxiety disorder, people who have little social support in their lives, and people who feel that they have little control over their lives are at greater risk of developing chronic pain syndromes, including TMJ.

In many cases TMJ results from a combination of psychological, anatomical, and functional factors rather than a single abnormality.

The symptoms of TMJ depend in part on its cause or causes. The most common symptoms are facial pain in front of the ears; headaches; sore jaw muscles; a clicking sound when chewing; a grating sensation when opening and closing the mouth; and temporary locking of the jaw. Some patients also report a sensation of buzzing or ringing in the ears. Usually, the temporomandibular joint itself is not painful. Most cases of TMJ are seen in women between 20–50 years of age.

Content licensed from:

Author Info: Paula Ford-Martin, Rebecca J. Frey PhD, The Gale Group Inc., Gale, Detroit, Gale Encyclopedia of Alternative Medicine, 2005

This feature is for informational purposes only and should not be used to replace the care and information received from your healthcare provider. Please consult a healthcare professional with any health concerns you may have.