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Alexandra George

171 Wexford-Bayne Rd. (Route 910) Suite 200
Wexford, PA

What is TMJ?


The Differences Between TMJ and TMJD

What is TMJ?

TMJ, is the common abbreviation of the anatomical feature known as the temporomandibular joint. The temporomandibular joints are the ball and socket joints that connect the upper and lower jaws to the temporal bones of the skull.

The TMJs are critical for our ability to move the jaw up and down, side to side, and back and forth. These motions are necessary for normal functions like chewing, making facial expressions, yawning, breathing, and even speaking. Everyone has two TMJ joints, with one positioned on each side of the head, just in front of the ear.

You can locate your TMJs by placing a finger in front of each ear and opening and closing your jaw. If your TMJs are in good condition, your jaw muscles will move your jaw smoothly up and down, back and forth, and side to side. In each TMJ, there is a small circle of cartilage that serves a cushion for your jaw as it moves, preventing your jawbone from rubbing against your skull.

What is TMJD?

TMJD is the common abbreviation of the medical condition known as temporomandibular joint disorder. TMJD is a painful and uncomfortable condition caused when one or both TMJ joints become injured or when the muscles that surround the joint become inflamed. The TMJ joints can become inflamed when the jaw is out of its natural place or teeth are crooked or crowded.

The most common cause of the TMJD is bite malocclusion in which the bite is bad. When this occurs, the muscles of the jaw are strained because they are forced to hold the jaw in an unnatural position.

TMJD can cause arthritis and chronic pain for patients if not treated. Many patients with TMJD have a diminished quality of life due to their condition.

In many cases, the terms “TMJ” and “TMJD” are used interchangeably- even by professionals- and are often confused by patients.

The exact number of people affected by TMJD is unknown, however, the National Institute of Dental and Craniofacial Research estimates that about 10 million Americans suffer from the condition. Many patients with TMJD go undiagnosed or have been misdiagnosed because the symptoms of the disorder are similar to other health conditions and symptoms vary from patient to patient. Learn more about the symptoms of TMJD here.

Click here to view an illustrative video on the differences between TMJ and TMD.