What is Temporomandibular Joint?
TMJ is an abbreviation for the anatomic structure known as the temporomandibular joint. The TMJ is the jaw joint that is located in front of the ear. This is where the lower jaw (mandible) hinges at the base of the skull to allow the mandible to open and function.
In the TMJ the mandibular condyle fits into a socket (glenoid fossa) at the base of the skull. During initial opening of the jaw, the condyle rotates in the fossa. During wide opening of the jaw, the condyle slides forward out of the fossa. In between the condyle and the glenoid fossa is a thick fibrous disc that acts like a cushion between the condyle and the fossa. The TMJ disc normally rides in unison with the condyle as it rotates and slides.
The disc is attached to the superior head of the lateral pterygoid muscle in front. Part of the superior head of the lateral pterygoid and the inferior head of the lateral pterygoid attach to the mandibular condyle in front. These muscle attachments assist in wide opening of the jaw as they pull the disc and the mandibular condyle forward. In back, the disc is attached to loose connective tissue that contains nerves and blood vessels. The entire TMJ is surrounded by a fibrous capsule.
Too often the term "TMJ" is used as a diagnostic term. Many people with pain in the area of the TMJ are told that they have "TMJ". That is like telling someone with abdominal pain that they have "appendix".
There are a variety of possible causes for pain in the region of the TMJ. The following is a list of possible causes of pain in the region of the TMJ:
Possible Causes of Pain in the TMJ Region
Muscle splinting/spasm (myofascial dysfunction)
Headache (migraine, cluster, etc...)
Trauma to the lower jaw (fracture, disruption)
TMJ disc dislocation
Arthritic changes of the mandibular condyle
Muscle inflammation (myositis)
Unbalanced bite (malocclusion)
Inflammation of the TMJ (capsulitis)
Tumor in the TMJ region
Only a thorough physical examination and diagnostic testing, if necessary, will reveal whether or not there is a problem with the actual TMJ itself.
How do I know if I have a TMJ problem?
TMJ disorders are characterized by functional limitations of the lower jaw. Typically patients complain of not being able to open normally or report pain with opening, speaking, or chewing. Patients may experience locking of the jaw in the open or closed position and may frequently experience clicks, pops, or grinding in the TMJ region.
Pain, alone, without functional limitations is not diagnostic of a TMJ problem. The cause or etiology for pain in the head and neck region is sometimes hard to find. Too often, when the cause of pain in the TMJ region is not readily apparent, patients are told that they have "TMJ" by default.
If you are experiencing pain in the TMJ region, only a thorough physical exam and diagnostic testing, if necessary, will determine the cause.
Who should I see if I think I have a TMJ problem?
Most patients will initially see their general dentist about a TMJ problem. Typically the dentist will then refer the patient to an oral and maxillofacial surgeon for further evaluation and recommendations for treatment. Some general dentists are experienced with TMJ disorders and may choose to diagnose the TMJ disorder and to initiate treatment themselves.
Dental specialists such as prosthodontists and orthodontists may also provide diagnosis of TMJ disorders and be involved in treatment. Medical specialists such as Ear, Nose and Throat (ENT) doctors may do the same.
Ultimately, however, if a patient needs surgical management of a TMJ disorder, an oral and maxillofacial surgeon will be involved.
How are TMJ problems diagnosed?
A proper TMJ evaluation starts with a thorough head and neck examination. A thorough medical history is also important. This includes any history of trauma to the jaw or history of previous TMJ problems and habits such as clenching and grinding the teeth.
If a TMJ problem is diagnosed, your doctor may order further tests to confirm the diagnosis and to determine the severity of the problem. The following table illustrates the tests used:
How do you treat a TMJ problem?
Treatment of TMJ disorders depends upon the nature and severity of the TMJ problem. The following table illustrates the various ways TMJ problems are treated and the indications for those specific types of treatment.
* services not provided by our office
What are the potential complications of TMJ surgery?
The nature and degree of complications related to TMJ surgery depend on the patient's anatomy, the degree of degeneration within the joint, and the surgical procedure itself. Patients who have had previous TMJ surgery are at higher risk for complications if additional TMJ surgery is performed on the same joint.
As with any surgical procedure, swelling, discomfort, bruising, infection and bleeding may occur. Numbness, which is usually temporary, may occur around the incision site .
Because of the close relationship between the frontal branch of the facial nerve and the TMJ, paralysis of the upper half of the face may occur on the side where the surgery was performed. This leads to the inability to raise the brow and to close the eye tightly. While this is usually temporary, in some instances problems with the frontal nerve have been known to be permanent.
As with all surgical procedures, the benefits of surgery must be weighed against the risks of surgery. This can only be determined after a thorough examination and discussion with your doctor.