Our TMJ acts like a sliding hinge, connecting our jawbones to our skulls. We have one joint on each side of our jaw (called the temporomandibular joint, or “TMJ”). TMJ disorders — a type of temporomandibular disorder or TMD — can cause pain in our jaw joints and in the muscles that control jaw movement.
The exact cause of a person’s TMJ disorder is often difficult to determine. Such pain may be due to a combination of factors, such as genetics, arthritis or jaw injury. Some people who have jaw pain also tend to clench or grind their teeth (bruxism), although many people habitually clench or grind their teeth and never develop TMJ disorders.
In most cases, the pain and discomfort associated with TMJ disorders is temporary and can be relieved with self-managed care or nonsurgical treatments. Surgery is typically a last resort after conservative measures have failed, but some people with TMJ disorders may benefit from surgical treatments.
WHAT IS THE TEMPOROMANDIBULAR JOINT (TMJ)?
The temporomandibular joint connects the lower jaw, called the mandible, to the bone at the side of the head — the temporal bone. If you place your fingers just in front of your ears and open your mouth, you can feel the joints. Because these joints are flexible, the jaw can move smoothly up and down and side to side, enabling us to talk, chew and yawn. Muscles attached to and surrounding the jaw joint control its position and movement. When we open our mouths, the rounded ends of the lower jaw, called condyles, glide along the joint socket of the temporal bone. The condyles slide back to their original position when we close our mouths. To keep this motion smooth, a soft disc lies between the condyle and the temporal bone. This disc absorbs shocks to the jaw joint from chewing and other movements. The temporomandibular joint is different from the body’s other joints. The combination of hinge and sliding motions makes this joint among the most complicated in the body. Also, the tissues that make up the temporomandibular joint differ from other load-bearing joints – such as the knee or hip. Because of its complex movement and unique makeup, the jaw joint and its controlling muscles can pose a tremendous challenge to both patients and health care providers when problems arise.
WHAT ARE TMJ DISORDERS (TMD)?
Disorders of the jaw joint and chewing muscles, and how people respond to them, vary widely. Researchers generally agree that the conditions fall into three main categories:
1. Myofascial pain involves discomfort or pain in the muscles that control jaw function.
2. Internal derangement of the joint involves a displaced disc, dislocated jaw, or injury to the condyle (a rounded protuberance at the end of some bones – forming an articulation with another bone).
3. Arthritis refers to a group of degenerative/inflammatory joint disorders that can affect the temporomandibular joint.
A person may have one or more of these conditions at the same time. Some people have other health problems that co-exist with TMJ disorders, such as chronic fatigue syndrome, sleep disturbances or fibromyalgia, a painful condition that affects muscles and other soft tissues throughout the body. These disorders share some common symptoms (which suggests that they may share similar underlying mechanisms of disease); however, it is not known whether they have a common cause.
WHAT ARE THE SIGNS AND SYMPTOMS?
A variety of symptoms may be linked to TMJ disorders. Pain, particularly in the chewing muscles and/or jaw joint, is the most common symptom. Other likely symptoms include:
* Radiating pain in the face, jaw, or neck;
* Jaw muscle stiffness;
* Limited movement or locking of the jaw;
* Painful clicking, popping or grating in the jaw joint when opening or closing the mouth;
* A change in the way the upper and lower teeth fit together.