TMJ refers to the temporomandibular joint, which connects the temporal bone of the skull to the mandible or lower jaw. It is by far the most active joint in the body, in motion not only during eating, drinking, and speaking, but also during breathing, swallowing (approximately 2000 times per day), and a variety of oral habits.

FOSSA

The illustrations above show the main
features of the temporomandibular joint.

1. The condyle or " ball" of the joint. It is a part of the mandible and is covered with fibrocartilage for smooth operation, remodeling, and repair.

2. The fossa or "socket " of the joint is located in the temporal bone in the base of the skull. Note the sloped wall of the front of the fossa; it provides a path for the condyles during opening and side-to-side movement of the mandible.

3. The joint disk. Positioned between condyle and fossa and moving down the slope of the fossa with the condyle, it allows the mandible a greater range of opening than would be possible with only a simple hinge action of the joint, in addition to distributing the biting and chewing stresses on the condyle over a greater area within the fossa.

The following video clips were made, using frozen cadaver specimens, by Dr. Per Westesson at the University of Rochester School of Medicine.

Normal Joint

Note the position of the disc, between the condyle and the anterior incline of the fossa. It is yellowish in color, indicating that is has no nerve or blood suppply; it is extremely tough and pressure resistant. Watch how it moves with the condyle, maintaining its position between condyle and fossa, and distributing the biting and chewing forces over a wide area. Note also the tissue behind the condyle: its pink color indicates its plentiful blood supply, but also its lack of dense, resistant, connective tissue. Its principal function is to maintain the position of the disc between condyle and fossa during function. It is, by its nature, not well suited to resisting the pressure of the condyle.

Displaced Disc With Reduction

Here we see the disc displaced anterior to the condoyl, possibly due to a variety of factors: trauma, habitual clenching of the teeth, jaw malpositioning, etc. Note that as the condyle moves forward it repositions itself in relation to the disc, resulting in the characteristic "pop" associated with disc displacement. Expecially important to note is the fact that, at rest, the condyle is displaced somewhat posteriorly, often causing impingement on the nerves which supply the joint, the ear canal, and the temporal area above the joint resulting in pain in these areas. Frequently the bite feels "off" due to the difference in condylar position with the disc displaced.

Displaced Disc Without Reduction

In this example, the disc has been displaced too far forward to be recaptured in normal function and the condyle operates full-time on the posterior attachment tissues. There is generally no sound in the joint, but the patient generally cannot open the mouth fully. At this point x-rays of the joint will show a decreased space between condyle and fossa, suggesting the disc displacement and resultant compression of the softer posterior tissues. As noted above, these tisues are not meant to resist the forces exerted by the condyle during function or parafunctional activities, such as clenching or grinding. Frequently, the result as shown in the next video, is joint degeneration.

Disc Perforation With Degeneration

Here the condyle has worn through the posterior attachment tissues and is now in direct contact with the fossa. There may or may not be significant pain by there is almost always a "grating" sound, a result of the bone to bone contact. Note the extensive flattening of the condyle doye to the lack of cushioning and force-distributing role of the disc. This can be expecially serious in older patients, where systematic arthritic conditions and osteoporosis can contribute to an already poor bone condition.

The term " TMJ" is also frequently used to define any pain in the area of the temporomandibular joints . The most common symptom is headache, but may often include ear pain, pain in the temples, around the eyes, or along the jaws. The images above show in red the areas to which pain is referred, and the X's show some of the areas which refer pain. Note that the source of the pain is often not the joints themselves, but rather various muscles, tendons, ligaments, and nerves in the head and upper neck. In fact, over 90 percent of patients presenting with "TMJ" actually have symptoms originating in the soft tissues, so-called Myofascial Pain.

Even in the presence of joint sounds, the main source of pain is most likely to be MYOFASCIAL.

These symptoms can be triggered by many of the same factors which cause joint damage (see above). Motor vehicle or sports accidents, especially rear end collisions, frequently do more damage to the soft tissues than to the joints.

Clenching or grinding the teeth ("bruxism") during sleep is one of the principal causes of myofascial pain referred to the temporomandibular joints. Factors contributing to bruxism include:

1. Stress. Ours is a highly stressful environment, given the demands of career, family, or other interpersonal relationships, economic uncertainty, daily commuting, health concerns, etc. Given the limited outlets available to "let off steam", many people internalize their stress in the form of bruxism, most often during sleep, and are therefore unaware of their even doing so!

2. Nutrition. In the American diet is high in refined sugars, which stress the nervous system by causing a blood sugar "roller coaster" as they cause a rapid rise in blood glucose due to their rapid absorption, followed by a steep plunge in glucose level as insulin is secreted to cope in with it. This pattern, when repeated several times a day, can have a serious effect on the neuromuscular system, especially seen in the chewing apparatus.

Caffeine, whether in coffee, tea, or soft drinks is not only a central nervous system stimulant, but also increases muscle activity (especially in the masseters, the major clenching muscles).

3. Sleep Disorders. Persons who get up in the morning feeling tired often do not receive enough oxygen during sleep, due to partial airway obstruction. Snoring is often -- but not always -- an indication of a possible problem.

Fibromyalgia sufferers have a very high incidence of sleep disorders, supporting the theory that this condition may be at least partially the result of poor oxygen supply to the tissues.

If you have any of the following complaints, consider having an evaluation by a TMJ or craniofacial specialist.

1. Headaches not helped by migraine medication, especially upon rising or late in the afternoon.

2. Facial pain.

3. Ear pain or stuffiness in the absence of infection (check with your ENT specialist first).

4. Pain and/or sounds in the temporomandibular joints.

5. Pain in the jaws, especially when chewing or upon arising.

6. Limited and/or painful jaw opening or deviation to one side when opening.

7. A feeling that your bite is "off".

8. Persistent neck pain, especially at the base of the skull, following a motor vehicle or sports accident.

9. Generalized tooth sensitivity, especially when chewing.

Examination

As with any medical complaint, proper treatment depends upon accurate diagnosis. This is in turn dependent upon a complete and accurate history and comprehensive, thorough examination.

The physical examination consists of palpation of the hard and soft tissues of the head and neck, with the goal of finding the trigger areas - the SOURCE, not merely the SITE of the problem. In addition to the clinical examination, x-rays are usually taken to determine whether or not any of the bony structures show changes, which might be a contributing factor in the patient's condition.

In addition, certain other tests may be indicated, such as:

Tek-scan -- a computerized analysis of the patient's bite, to determine the presence and extent of any malocclusion.

Pulse oximetry -- a take-home instrumented test to measure oxygen saturation during sleep. This is strictly a screening procedure, used to ascertain the need for a more comprehensive sleep study.

Pharyngometry -- a sonar-like procedure to determine the location and extent of airway obstruction, possibly contributing to sleep apnea.

Rhinometry -- similar to pharyngometry, used to determine nasal airflow and the need for possible referral to an ENT physician for evaluation and possible treatment.

Treatment

During all phases of treatment -- from the initial consultation to when maximum medical improvement is reached -- the patient is informed of his/her status and is involved in treatment. At the first visit, whether or not treatment is elected, each patient is given condition-appropriate home exercises to perform, which may be augmented with other procedures as the case progresses.

Orthotics or "splints" are frequently employed, their design dependent on the patient's individual problem. They may serve to relax muscles, decompress inflamed joints, relieve nerve impingements, stabilize jaw and/or disk position, and compensate (temporarily) for bite imbalance, or a combination of many functions. They are adjusted periodically as healing progresses, with the goal of weaning the patient from dependence on them or, at the very least, limiting their use to a nighttime or as needed basis.

A very large percentage of our patients receive physical therapy outside of our office. Since most physical therapy is administered one or two times per week, it makes sense to receive that treatment at a facility close to the patient's home or work. Also, given the number of patients in treatment at any one time, our facility has neither the space nor personnel to handle such a load and, given the large number of excellent, well-trained Physical Therapists, Neuromuscular Therapists, Craniosacral Therapists, Massage Therapists, and other rehabilitation personnel in the Denver area, we feel that we need not duplicate this valuable resource!