What two movements does the TMJ perform?

Answer 1

The TMJ (Temporomandibular Joint) is arguably the most complex joint in the body.

There are three basic types of joints in the human body, and the TMJ incorporates characteristics of all three.

1. The hinge joint, like a knee or elbow, the joint moves like a door opening and closing.

2. The ball and socket joint, like the hip or shoulder, a wide range of motion is achieved by circular motion around a central point.

3. The glide joint, like the wrist wherein motion is achieved when bones essentially glide together and apart.

The TMJ acts like a hinge joint when you simply open and close your mouth. It acts like a ball and socket joint when you chew your food, and it acts like a gliding joint when you jut your jaw forward.

To add to the complexity of the TMJ, it is the only joint in the body wherein its motion directly affects the other joint on the other side of the head.

The TMJ also is home to one of the body's fastest reflexes. The reflex causes the mouth to open quickly in the event the teeth encounter an unexpected hard object that could fracture the teeth. If you doubt this, hide a small pebble in your soup.