HEADACHE AND FACIAL PAIN: TEMPOROMANDIBULAR JOINT DISORDERS: OVERVIEW AND ANATOMY

An estimated 75 percent of the U.S. population has experienced one or more signs or symptoms of temporomandibular joint disorders (TMD). Most TMD symptoms are temporary and come and go over time, requiring little or no professional intervention. An estimated 5 percent to 10 percent of the U.S. population will require professional treatment. People with TMD usually have more than one symptom. The disorder rarely has a single cause.

TMJ Anatomy

The temporomandibular joint is a "loose-fitting," rotating-sliding joint with a fibrocartilage covered, football-shaped ball (condyle), fibrous pad (disc), fibrocartilage lined socket (fossa), ligaments, tendons, blood vessels and nerves. The fibrous disc functions as a moving shock absorber and stabilizer between the condyle and the fossa. As the jaw opens, the condyle rotates and slides forward with the disc.

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

There are two types of TMD — muscle related and joint related.

· Myogenous TMD (muscle related) usually results from overwork, fatigue or tension of the jaw and supporting muscles. This type of TMD causes jaw-ache, headache and/or an ache in the back of your neck.

· Arthrogenous TMD (joint related) usually results from inflammation, disease or degeneration of the hard or soft tissues within the TMJ. Inflammation, disc dislocation and degenerative arthritis are the most common arthrogenous disorders of the TMJ.