What causes TMJ?

TMJ, or temporomandibular joint disorders, can be caused by injury to the jaw joint, grinding of the teeth, dislocation of the soft cushion or disc in the jaw joint, or by osteoarthritis or rheumatoid arthritis. According to the Mayo Clinic, however, in many cases, the cause of TMJ is unclear.

WebMD reports that common symptoms include soreness in the face and around the jaw, tenderness in the neck and shoulders, hearing a clicking sound in the jaw when opening the mouth or locking of the jaw joint, and difficulty or discomfort when chewing. The Mayo Clinic advises that it's time to see a doctor when the pain becomes persistent, or when it becomes impossible to fully open the mouth.