Conditions InDepth: Temporomandibular Disorders (TMD)

TMD involves the 2 joints that link the lower jaw to the skull. These joints let the mouth open and close. They are in front of your ears.

There are 3 types of TMD:

  • Myofascial pain of the muscles that control jaw function
  • Joint derangement, such as a displaced disc, dislocated jaw, or injury to the bone
  • Arthritis of the temporomandibular joint

Adult Skull Showing Temporomandibular Joint

Adult Skull Showing TMJ and Muscles
Copyright © Nucleus Medical Media, Inc.

You may have TMD if:

  • The temporomandibular joints (TMJ) are often swollen and sore.
  • The muscles that work the joints spasm often.
  • The disc that rests between the joint and the skull is worn out or out of place.
  • You have problems moving your jaw.
  • Your bite is off or not in line.
  • You have clicking in when you move your jaw.

The exact cause of TMD is not known. Some people have had accidents or injuries of the jaw, but many others have not. Some causes may be:

  • Grinding the teeth or clenching the jaw because of stress
  • Arthritis of the joint
  • Past injury or trauma to the joint
  • Facial bone defects
  • A bite that is off or not in line

Enlargement of TMJ With Jaw Open

Enlargement of TMJ with Open Jaw
Copyright © Nucleus Medical Media, Inc.

TMD symptoms may originate within the joint itself or from the muscles that surround the joint. The treatment of these 2 variants of TMD may differ.



Temporomandibular disorders. American Association of Oral and Maxillofacial Surgeons website. Available at: Accessed July 29, 2019.
Temporomandibular disorders. EBSCO DynaMed website. Available at: Updated February 20, 2018. Accessed July 29, 2019.
Temporo-mandibular joint (TMJ) pain. ENThealth—American Academy of Otolaryngology-Head and Neck Surgery website. Available at:
...(Click grey area to select URL)
Updated January 2019. Accessed July 29, 2019.
TMJ. Mouth Healthy—American Dental Association website. Available at:
...(Click grey area to select URL)
Accessed July 29, 2019.
TMJ (temporomandibular joint and muscle disorders). National Institute of Dental and Craniofacial Research website. Available at: Accessed July 29, 2019.
Last reviewed June 2019 by EBSCO Medical Review Board Daniel A. Ostrovsky, MD
Last Updated: 10/18/2019

EBSCO Information Services is fully accredited by URAC. URAC is an independent, nonprofit health care accrediting organization dedicated to promoting health care quality through accreditation, certification and commendation.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

To send comments or feedback to our Editorial Team regarding the content please email us at Our Health Library Support team will respond to your email request within 2 business days.