The temporomandibular joint (TMJ) is the hinge joint that connects the lower jaw (mandible) to the temporal bone of the skull. Temporomandibular disorders (TMD) occur as a result of problems with the jaw, jaw joint, and surrounding facial muscles that control chewing and moving the jaw.
This joint is immediately in front of the ear on each side of your head. The joints are flexible, allowing the jaw to move smoothly up and down and side to side and enabling you to talk, chew, and yawn. Muscles attached to and surrounding the jaw joint control its position and movement.
The cause of TMD is not clear, but dentists believe that symptoms arise from problems with the muscles of the jaw or with the parts of the joint itself. Injury to the jaw, temporomandibular joint, or muscles of the head and neck such as from a heavy blow or whiplash can cause TMD. Other possible causes include grinding or clenching the teeth, which puts a lot of pressure on the TMJ, dislocation of the soft cushion or disc between the ball and socket, presence of osteoarthritis or rheumatoid arthritis in the TMJ, or stress, which can cause a person to tighten facial and jaw muscles or clench the teeth.