The Temporomandibular Joint

The temporomandibular joints (TMJ) are among some of the most frequently used joints in the body, allowing us to talk, chew, yawn, swallow and sneeze. The TMJ are located on each side of the cranium.

To find your TMJ, place your fingers in front of each ear and open your mouth, you will feel an indentation beneath your finger.

The two bones that form the TMJ are the mandible (jaw) located inferiorly, and the temporal bone of the skull (located more superiorly) (see Figure 1).

A disc that is connected to the capsule divides the joint cavity into inferior and superior spaces. (see Figure 2)

Temporomandibular joint dysfunction (TMD) is often overlooked. Some of the more common symptoms include clicking or popping with opening or closing of the mouth, pain around the jaw joints, locking of the jaw, headaches and an improper bite (teeth do not fit together properly) (see Figure 3).

Most often, TMD can be treated conservatively. However, it is important that a qualified clinician such as a physical therapist, dentist, or orthopedist is consulted for an accurate diagnosis since many conditions can mimic the signs and symptoms common to TMD.

Movements of the TMJ

Both TMJ must work in coordination in order to allow normal movement to occur. The TMJ allow us to open and close the mouth, protrude, retract, and laterally move the jaw (mandible) right and left. Normally, opening should be about 35-40 mm.

A good test to determine normal opening is being able to fit about 2 or 3 knuckles into your mouth. If you cannot open your mouth this wide, you may have a hypomobile (decreased range of motion) TMJ.

Muscles Acting on the TMJ

The muscles of the TMJ are also known as the muscles of mastication, allowing the mandible to move for the purpose of chewing and speaking. The primary muscles involved are the following: temporalis, masseter, medial pterygoid, and lateral pterygoid (see Figures 4-6).

The muscles of each TMJ must work together. Dysfunction occurs when the muscles fire out of synchrony leading to muscle spasm, pain and inflammation of the TMJ. When in a state of muscle imbalance, subluxation of the joint is also possible.

Temporomandibular Joint Dysfunction

The most common dysfunctions associated with the TMJ are inflammation, muscle imbalances, hypomobility, and hypermobilty. The synovium, retrodiscal tissue and the capsule are some of the tissues that can become inflamed in the TMJ.

Possible causes for TMJ dysfunction:

  1. Trauma to the joint-blow to the jaw or head
  2. Excessive stress to the joint from gum chewing, fingernail biting, yawning, chewing on a pen, chewing on ice, and grinding teeth
  3. Jaw abnormalities, missing teeth, poor bite (malocclusion)
  4. Resting the head in the hand
  5. Arthritis of the TMJ
  6. Dislocation of the disc
  7. Myofascial pain dysfunction
  8. Postural abnormalities, especially with a forward head posture
  9. Whiplash injury
  10. Prolonged mouth and upper respiratory breathing
  11. Thumb sucking
  12. Ligamentous laxity
  13. Birth/Congenital trauma

Common signs and symptoms of TMJ dysfunction:

  1. Clicking or popping with opening or closing
  2. Pain at rest or with opening/closing of jaw
  3. Decreased ability to open the jaw (hypomobility)
  4. Neck pain
  5. Tooth sensitivity
  6. Dry or burning sensation in mouth
  7. Uncomfortable bite
  8. Forehead or temple headache
  9. Buzzing or ringing in ears
  10. Hearing loss

Self-care for Management of Symptoms

  1. Habit Modification: Try to avoid the activity that is causing the increased stress to the joint such as nail biting, gum chewing, and ice biting. You may see a dramatic change in your symptoms by simply modifying these habits.
  2. Diet Modification: Eat a diet of soft foods in addition to chewing evenly. You may want to cut your food into small pieces which will help decrease overuse of the TMJ.
  3. Pharmacological: Anti-inflammatory medications such as aspirin or ibuprofen can help to decrease pain and inflammation. However, you should consult with your physician before taking any of these medications.
  4. Hot compresses: Use a washcloth soaked in warm water or a commercial moist hot pack over the area of pain or tenderness. This will help reduce any muscle spasm you may be experiencing. Keep the compress on for about 10- 15 minutes. If the spasms are severe, try to use these compresses hourly.
  5. Dental Appliances: You may need some type of intra-oral splint, nightguard or other appliance which can be given by your dentist or physical therapist upon diagnosis. This may help to stabilize the TMJ so the muscles, teeth, and joints work together without adding additional strain to the TMJ.
  6. Cold packs: These can be used to help reduce any swelling, pain and muscle spasm. Leave the cold pack on for about 10-15 minutes. If symptoms are severe, use ice pack once every hour.
  7. Positioning: The best position to keep your TMJ in is with your teeth slightly apart and lips together. Placing the tongue on the roof of the palate (top of the mouth) is also wise to ensure the position is kept. In addition, try to breathe through your nose as much as possible.
  8. Stress Management: Stress is a common contributing factor to TMD. If stress is the contributing factor to your TMD, deep relaxation training, breathing, meditation or biofeedback are of great benefit.
  9. Posture: A forward head posture is a big contributor to TMD. (see Figure 7) Try to practice good posture, especially when sitting for long periods of time. In addition, you may want to invest into a lumbar roll, which will help maintain the proper body positioning when sitting for long periods of time. You can find a lumbar roll at your local surgical supply store. The following exercises can help improve your posture. Remember, these exercises should be pain-free.

Chin Tucks

Leading with your chin, try to press your head back. Do 3 sets of 15, twice a day. Try to do this exercise in front of a mirror. (see Figure 8)

Scapular Retractions

Use a theraband or other kind of elastic rubber band for this exercise. Tie the band around a stable object, such as a hinge on a door, the band should be level with your chest height.

Holding both two ends of the band in the hands, pull your arms away from the door. Keep the elbow flexed at 90 degrees. Bring the arms back towards the door, slowly controlling the resistance given by the band. DO 3 sets of 15, once a day. (see figure 9)

  1. Massage: Try to gentle massage over and around the area of discomfort. This will help to relieve any muscle spasm you may experience. This can be done with your mouth open and closed. Try to massage the area for about 10- 15 minutes.

When to seek professional help?

If your symptoms last for more than 2-3 weeks, you should seek professional assistance. For a true diagnosis of TMJ dysfunction, a comprehensive history and physical exam along with other diagnostic procedures such as a x-ray and lab tests are necessary. The majority of the time, conservative non-invasive treatment relieves the symptoms.

Figure References

  1. Advance Magazine for Physical Therapists and PT Assistants. May 1, 2000, pg.38.
  2. Orthopedic Physical Assessment. David J. Magee. WB Saunders, 1987.
  3. Management of Common Musculoskeletal Disorders Physical Therapy Principles and Methods. Hertling, D.and Kessler R. 2nd edition, J.B. Lippincott Company, 1990.
  4. Clinical Orthopedic Physical Therapy. Richardson, J.K. and Iglarsh A.I. W.B. Saunders Company, 1994.
  5. Clinical Orthopedic Physical Therapy. Richardson, J.K. and Iglarsh A.I. W.B. Saunders Company, 1994.
  6. Clinical Orthopedic Physical Therapy. Richardson, J.K. and Iglarsh A.I. W.B. Saunders Company, 1994.