Illustration copyright 2000 by Nucleus Communications, Inc. All rights reserved. http://www.nucleusinc.com

The temporomandibular (TM) joints join the skull and lower jawbone (mandible). These gliding “ball and socket” joints are located just in front of each ear, and they move when a person opens and closes their mouth.

The TM joints are stabilized by muscles that attach directly to the jawbone. They are separated by a disc made of cartilage, which keeps the two bones from rubbing together.