The temporomandibular joint (TMJ)

What is the temporomandibular joint?

As its name suggests, the temporomandibular joint (TMJ) is located at the junction of the temporal bone of the skull and the lower jaw (mandible), on either side of the face, in front of the ears. Each human has 2 ATMs.

ATMs play a key role in essential functions involving opening and closing the mouth, such as speaking, chewing, swallowing and even yawning. They are therefore the most stressed joints of the human body.

In addition, they can perform slides and forward and backward (antero-posterior) pivots, in addition to slight left to right movements, in a synchronized manner. They also support functions that involve the teeth and are subjected to high forces. All these features give them the title of the most complex joints of the human body.

The components of TMJ

The TMJ is made up of several elements, the main ones being:

• the base of the skull where the temporal bone is located and the condyle of the mandible, the small ball at the end of the rising branch of the lower jaw bone;
• small muscles that allow the mandible to move;
• several ligaments and tendons;
• blood vessels and nerves;
• articular surfaces between which an articular disc, also called a meniscus, is positioned. This disc serves as a small cushion between the condyle and the skull during mandibular movements to avoid any friction of the joint surfaces. It also absorbs and redistributes significant chewing forces. This meniscus also has the particularity of following the mandible into the articular fossa during jaw movement;
• synovial fluid to ensure fluidity of jaw movement.

The ear canal is located behind the TMJ.

These elements, as well as other surrounding and related structures, must be in perfect balance to function properly.