Temporomandibular joint (TMJ) disorders, also called temporomandibular disorders (TMD) or craniomandibular disorders (CMD), are a group of disorders affecting the TMJ or jaw joint and its surrounding muscles. Examples of TMJ disorders include:
- Joint disorders, such as displacement of the articular disc of the TMJ (internal derangement), traumatic injuries, hypermobility, or hypomobility of the TMJ.
- Joint diseases, such as degenerative joint disease, arthritis, resorption of bone, cracks in the articular cartilage and/or bone, or death of bone tissue due to lack of blood supply.
- Muscular disorders, such as pain, shortening, enlargement, hardening, or involuntary contractions of the jaw muscles surrounding the TMJ.
- Birth disorders causing growth disturbances of the lower jaw (mandible) and/or other areas surrounding the TMJ.
- Tumors of the bony components of the TMJ.
Psychological, genetic, and/or hormonal factors may indirectly cause TMJ disorders by disturbing the normal functioning of the joint. TMJ disorders may also result from no obvious cause. TMJ disorders may develop suddenly or may take months to years before causing any symptoms or prompting medical attention.
The TMJ is a paired, synovial, and load-bearing joint1 that connects the mandible (lower jaw) to the temporal bone on the side of the head. The mandibular portion of the joint is composed of the mandibular condyle, which articulates with the mandibular fossa (depression) of the temporal bone. Both the mandibular condyle and fossa are lined with fibrous connective tissue, which is less prone to damage and has good repair properties. Between the mandibular condyle and fossa, is an articular disc that lies on top of the round condylar head and is held in place by soft tissues. Several muscles and ligaments attach to the articular disc and other bony components of the TMJ.
Each TMJ is located in front of the ear and enables movements in 3 directions—forward and back, side to side, and up and down. The TMJ performs the functions of both a hinging (ginglymus) joint and a sliding (arthrodial) joint. TMJ disorders may affect one or both TMJs and may impair functions, such as chewing, talking, swallowing, sleep, and/or breathing.
How Does a TMJ Disorder Feel?
Depending on the cause of the TMJ disorder, symptoms may vary. Common characteristics of TMJ disorders may include one or more of the following:
- Headache, including pain in the temples, forehead, behind the eye, and/or around the ear
- Pain in the jaw muscles, face, sinuses, neck, and/or shoulders
- Ear symptoms including pain, ringing, buzzing, and/or congestion in the ears
- Jaw symptoms including clicking, popping, and/or grating sounds while opening and closing the mouth; limited jaw opening, and pain in the TMJ
- Improper bite or inability to bring the teeth together
Additionally, TMJ disorders may also cause disturbed sleep, dizziness, or vision problems in some people. Jaw sounds without associated pain or other TMJ disorder symptoms may not always indicate a TMJ disorder, and mostly go away on their own.
The Course of TMJ Disorders
An estimated 5% to 12% of the population is affected by TMJ disorders.2 They commonly affect people in the age group of 20 to 40 years, with women at a higher risk than men. TMJ disorders are also common among people with misaligned bites.3
Often, a particular event or injury results in a TMJ disorder, which may occur suddenly or develop over a period of time. A long-term outlook for TMJ disorders depends on the cause and severity of the underlying condition. In most cases, TMJ disorders may be well managed with an accurate diagnosis and medical care.
When a TMJ Disorder Is Serious
In rare cases, TMJ disorders causing one or more of the following symptoms need prompt medical evaluation:
- Severe facial pain, especially if it seems different from previous TMJ pain
- Facial numbness
- Vision loss
- Difficulty hearing
- Dry mouth
- Weakness and/or dizziness
These symptoms could indicate serious medical conditions, such as facial neuralgias, sinus or salivary gland tumors, and/or acoustic neuromas. A doctor can diagnose TMJ disorders in order to begin an appropriate treatment program.