Temporomandibular joint (TMJ) dislocation commonly follows extreme opening of the mouth (eg, eating, yawning, laughing, singing, vomiting, dental treatment) and is less often caused by trauma. Treatment consists of exclusion of a fracture, manual reduction, soft diet, and referral to an oral and maxillofacial surgeon.
This topic will review the evaluation and reduction of TMJ dislocations. The evaluation and management of jaw fractures is covered separately. (See "Jaw fractures in children" and "Facial trauma in adults".)
MECHANISM OF INJURY
Anterior TMJ dislocation may occur with trauma, but most often follows extreme opening of the mouth during eating, yawning, laughing, singing, vomiting, or dental treatment [1,2]. Dislocation also can result from dystonic reactions to drugs . Symmetric mandibular dislocation is most common, but unilateral dislocation with the jaw deviating to the opposite side also can occur.
Superior and posterior dislocations of the TMJ are rare and usually associated with trauma . Superior dislocations occur in association with mandibular fossa fractures. Posterior dislocations may be associated with disruption of the external auditory canal or fracture of the temporal plate.
The temporomandibular joint (TMJ) is the articulation of the temporal and mandibular bones (figure 1) . TMJ dislocation occurs when the condyle travels anteriorly along the articular eminence and becomes locked in the anterior superior aspect of the eminence, preventing closure of the mouth (figure 2) . This results in stretching of the ligaments, and is associated with severe spasm of the muscles that open and close the mouth (ie, the masseter, medial pterygoid, and temporalis) (figure 3) [6,7]. The resultant trismus prevents the condyle from returning to the mandibular fossa.