Know the Warning Signs! TMJ stands for temporomandibular joint, which is the connecting joint between the jawbone and skull. When muscles, jawbone, and teeth all operate properly, biting and chewing is coordinated to be smooth and pain-free. Sometimes, however, things can get "out of whack." When teeth don't line up properly in the upper or lower jaws, the extra muscular stress causes muscle and jaw pain. Symptoms range from mild [...]