Patients present with the inability to close the jaw, usually after yawning, laughing, taking a large bite of food, suffering a traumatic jaw injury, or having a dystonic drug reaction. Such patients have difficulty enunciating clearly. Although they usually have only mild to moderate discomfort, they may have severe pain anterior to the ear. A depression can be seen or felt in the preauricular area, and the jaw may appear to be protruding forward (underbite). If only one side is dislocated, the mandible appears tilted and lies lower on the affected side.