The lower jaw is connected to the skull by a hinge called the temporomandibular joint. There are actually two, one on the left and one on the right, where the mandible meets the lower part of the jaw, which is called the temporal bone. The TMJ is the joint that makes it possible to open and close your mouth, and all that implies.
Pain in the TMJ used to be called Costen’s syndrome, after a doctor named James Costen who examined the condition in the 1930s, but is now known simply as temporomandibular joint disorder, or TMD. There are a number of possible causes for this pain; TMD is more a symptom than a specific condition. However, regardless of the specific cause, the pain can interfere with much of someone’s daily life, including talking and chewing.
Doctors are unsure what is behind many cases of TMD, though some causes are known. Bruxism, or grinding the teeth, is occasionally the culprit. This is often a nervous habit, but it can cause several kinds of damage. Stress at the joint—the cartilage disk, the jaw, face, and neck muscles, nerves and blood vessels, even teeth—appears to be the cause a significant portion of the time. Arthritis and stress are also known causes not infrequently.
In addition to jaw pain, temporomandibular joint disorder can cause pain around the ear and facial aching. Other symptoms include painful chewing and swallowing, an uncomfortable or uneven bite, a locking of the joint, or an audible clicking when you try to use the joint by opening or closing your mouth. TMD patients are also particularly prone to headaches,
Treatment generally involves painkillers or muscle relaxants as the initial approach. Botulinum toxin, or Botox, is used in some cases. inflammation is dealt with by using corticosteroids. Tricyclic antidepressants seem to be helpful for some, as is cognitive-behavioral therapy, a technique generally reserved for mental illnesses. A bite guard can help with bruxism. In extreme cases, doctors can inject fluid into the joint directly.