What Does It Stand For?
TMJ is short for temporomandibular joint. There’s one on each side, and they attach your jaw to the bottom of your skull. The muscles near them let you open and close your mouth. But sometimes, the joints get out of line or don’t move as they should. You might have heard that problem called TMJ, but it’s actually TMD — temporomandibular joint disorder. Up to 15% of adults, mostly ages 20 to 40, have it. It happens more in women than in men.