The temporomandibular joint (TMJ) acts as a sliding hinge, connecting the lower jawbone (mandible) to the temporal bones of the skull. This complex joint allows for the wide range of motion necessary for speaking and chewing. A TMJ dislocation occurs when the joint moves out of its normal position, representing a serious and painful event that requires immediate medical intervention.
Anatomy and Identifying a TMJ Dislocation
The TMJ is formed by the mandibular condyle, the rounded end of the jawbone, which fits into a socket on the skull called the glenoid fossa. An articular disc cushions these bony surfaces, enabling smooth, gliding movements. A bony ridge, known as the articular eminence, sits in front of the fossa and acts as a barrier to prevent the condyle from sliding too far forward during normal jaw opening.
A true TMJ dislocation, or luxation, occurs when the condyle moves completely forward beyond the articular eminence and becomes locked in that position. This condition prevents the patient from closing their mouth without assistance. The muscles of mastication go into painful spasm, called trismus, which holds the jaw open. This differs from a subluxation, which is a partial, self-reducing displacement where the condyle momentarily slips past the eminence but returns to the fossa on its own.
The most common type is an anterior dislocation, often triggered by non-traumatic events involving extreme mouth opening. These events include excessive yawning, prolonged dental procedures, deep coughing, or a seizure. Underlying factors like pre-existing ligamentous laxity or hypermobility can make a person more susceptible to this injury.
The symptoms of a dislocation are typically unmistakable, with the primary sign being the inability to close the mouth. Patients experience intense pain in the joint and surrounding temporal region. A noticeable shift in the jaw alignment, or malocclusion, is common, and the jaw may protrude forward. Because the mouth is fixed open, profuse drooling can occur, and a depression may be felt in the preauricular area.
Emergency Treatment and Joint Reduction
A TMJ dislocation is an acute injury that necessitates immediate medical attention, typically in an emergency room setting. A healthcare provider, such as an emergency physician or an oral surgeon, will perform a closed reduction, which is a manual manipulation to reposition the joint. This procedure must be done quickly, as prolonged dislocation leads to severe muscle spasm that makes reduction significantly more difficult.
Before attempting the reduction, the medical team administers medication to manage pain and alleviate muscle spasm. Intravenous sedatives and analgesics, such as midazolam, may be used for procedural sedation to relax the jaw muscles. Local anesthesia, such as a nerve block targeting the deep temporal or masseteric nerves, can also be employed to reduce pain and reflex muscle guarding.
The standard manual technique, often called the Hippocratic method, involves the provider placing protected thumbs over the patient’s lower molar teeth, with fingers wrapped under the chin. Pressure is applied downward and backward to disengage the condyle from the front of the articular eminence. Once the condyle clears the eminence, the jaw is guided backward into the glenoid fossa.
The successful reduction is often accompanied by a distinct click or snap as the condyle returns to its socket. Immediate stabilization of the joint is the next step to prevent re-dislocation, which is common due to the stretching of the joint capsule and ligaments. While this manual process is highly effective for acute dislocations, any attempt at self-reduction should be strictly avoided due to the risk of further injury or fracture.
Recovery and Long-Term Management
Following a successful reduction, the immediate focus shifts to resting the joint to allow the stretched capsule and ligaments to heal. The patient must adhere to a strict soft diet for one to two weeks, avoiding food that requires significant chewing. Jaw movement must be limited, meaning the patient should refrain from excessive mouth opening, such as wide yawning, yelling, or chewing gum.
Nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended to manage residual pain and inflammation in the joint. In some cases, a soft cervical collar or a restrictive bandage may be used temporarily to limit the range of jaw motion and provide external support. This immobilization helps ensure the condyle remains securely in the fossa during the initial healing period.
Long-term management focuses on preventing recurrence, which is a risk particularly if the underlying cause was hypermobility. Patients who experience recurrent episodes may be referred to a specialist, such as an oral and maxillofacial surgeon or a dentist specializing in TMJ disorders. These specialists assess for chronic issues like a shallow fossa or ligamentous laxity.
For frequent recurrence, non-surgical options may include injections of autologous blood or sclerosing agents into the joint capsule to induce scar tissue and tighten the supporting structures. If conservative treatments fail, surgical procedures, such as an eminectomy to flatten the bony eminence, may be considered to allow the jaw to move freely without locking. Physical therapy, including gentle exercises to strengthen the muscles and improve coordination, is beneficial in restoring normal joint mechanics and preventing future incidents.