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Dislocation of the Temporomandibular Joint (TMJ)

Dislocation of the Temporomandibular Joint (TMJ)

What Is It?
Symptoms
Diagnosis
Expected Duration
Prevention
Treatment
When To Call A Professional
Prognosis
Additional Info

What Is It?

The temporomandibular joint (TMJ), just in front of the lower ear, is the joint that allows the lower jaw to move. Occasionally, the TMJ can dislocate and lock in an open position. This happens when the joint opens widely and the ball of the jaw joint gets stuck out of place. The TMJ is a ball-and-socket joint, just like the hip or shoulder. However, it is different from other joints in the body in that it "dislocates" as part of its normal functioning. When the mouth is opened wide, the ball (called the condyle) comes out of the socket and moves forward, going back into place when the mouth is closed. The condition described as a dislocation of the TMJ occurs when the condyle goes a bit too far and gets lodged in front of a bony prominence called the articular eminence. This occurs most often when the ligaments that normally keep the condyle in place are somewhat loose, which allows the condyle to move beyond the articular eminence. The surrounding muscles then often go into spasm and hold the condyle in the dislocated position.

Symptoms

The jaw locks in an open position. The condition can cause significant discomfort until the joint is returned to the proper position.

Diagnosis

The diagnosis is based on the position and immobility of the jaw.

Expected Duration

The problem is corrected as soon as the join is relocated. However, the area can be tender for a few days.

Prevention

TMJ dislocation can become chronic among patients with loose TMJ ligaments. To keep recurrence to a minimum, patients are reminded to be conscious of limiting the range of motion of their jaw - placing their fist under their chin when they yawn, for example, to keep from opening their mouths too widely. Conservative surgical treatments also can help prevent recurrence. One type of surgery involves wiring the
jaw shut for a period of time, which causes the ligaments to become less flexible and restricts their movement. Another involves putting a fishing-line-type wire between the top and bottom jaws to prevent the jaw from opening too widely. In certain cases, more extensive surgery may be necessary. One procedure, called an eminectomy, removes the articular eminence so the ball of the joint can no longer get stuck in front of it. Another, often done arthroscopically, involves injecting agents into the TMJ ligaments to tighten them.

Treatment

The surrounding muscles need to be relaxed to return the condyle (the ball of the joint) to its normal position. In the emergency room or a doctor's office, patients usually will receive an injection of local anesthesia in the jaw joint, followed by a muscle relaxant to alleviate the spasms, so the dislocation can be corrected. To move the condyle back into the correct position, a doctor or dentist will manually pull the lower jaw downward and tip the chin upward to free the condyle from entrapment beyond the articular eminence. Then, the doctor or dentist guides the ball back into the socket. After the joint is relocated, a soft or liquid diet is recommended for several days to minimize jaw movement and stress. Patients are advised to avoid foods that are hard to chew, such as tough meats, carrots, hard candies or ice cubes, and to be careful not to open the mouth too widely.

When To Call A Professional

A TMJ dislocation requires an immediate visit to the doctor or hospital emergency room to have the joint put back in place.

Prognosis

Excellent for returning the dislocated ball of the joint to the socket. However, chronic dislocation is common in some people.

Additional Info

The TMJ Association
P.O. Box 26770
Milwaukee, WI 53226-0770
Phone: (414) 259-3223
www.tmj.org/

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