The articular disk separates the condyle head of the mandible and the skull. When this disk is misplaced it will cause Temporal Mandibular Joint Dysfunction (TMJ).

The onset of pain is gradual, progressively increasing over several days or months. It is aggravated by chewing and opening and closing the mouth.

Joint clicking, popping, or grinding are often felt and/or heard and there is pain on opening and closing the mouth, or, sometimes, just by moving the head on the neck.