The temporomandibular joint (TMJ)
Each person has two, located on each side of the face, immediately in front of the ears. These are the joints that join the temporal bone of the skull to the lower jaw (mandible). During mouth movements, the TMJs open and close like a hinge, sliding forwards, backwards, from side to side. During chewing, they experience enormous pressure.
Like other joints, the surfaces of the TMJs are covered with cartilage. Like the knee, the two parts of the jaw joint are separated by a small disc, the meniscus, which keeps the bones from rubbing against each other. The muscles that open and close the mouth help stabilize these joints.