TempoMandibular Joint

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The Temporomandibular joint or TMJ joint allows your jaw to open and close in activities such as talking and chewing. Many individuals with jaw pain are not aware of the signs and symptoms of a TMJ dysfunction despite having jaw pain and seek dental care to fix the problem. Physical therapists are well equipped to treat the TMJ if patterns lead clinicians to believe a dysfunction is present.

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First, The TMJ is located just in front of the external auditory meatus (your ear canal) so pain will often be just in front of the ear canal with active opening and closing of the mouth. The muscles that support the TMJ are called your muscles of mastication and just like any other joint in the body if imbalances, weakness or muscular restriction is present it can affect proper joint function causing pain or clicking.

Referral pain from these muscles specifically the pterygoids, temporalis and masseter muscles can occur around the head and face and be interpreted as headache symptoms. Factors that increase likelihood of TMJ dysfunctions include: decreased jaw depression (mouth opening, 50 mm is normal which is about 2-3 finger width), decreased lateral movements of the jaw, clicking, headaches or trauma to the jaw. Additionally, Certain parafunctional habits also can put you at greater risk for developing a TMJ dysfunction or exacerbating a current one.

These habits include:

  • chewing on pens or pencils,

  • bruxism ( grinding of the teeth ),

  • resting chin on hands while sitting at a desk or table.

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Last, certain postural malallignments can also lead to TMJ dysfunction. Examples are: Malocclusion where the upper and lower teeth do not align properly (which would require a dental referral), forward head posture, and decreased cervical spine mobility. Forward head posture occurs when the lower neck flexed forward causing the upper neck and head to compensate into extension. This commonly occurs with computer based work where prolonged sitting occurs. This cervical posture can change the axis of the TMJ joint causing clicking and decreased ability to open the mouth. The TMJ also has a disc present in the joint space similar to the spine to help the joint handle compressive forces. Chronic clicking with opening and closing of the jaw can be a sign that the disc is resting in an anterior position. This is referred to as internal derangement and can also impact the mouths ability to open. The above dysfunctions can be improved through careful joint mobilization, postural re-education and strengthening to muscles supporting the TMJ. Physical therapist and dentists can work together by identifying both at risk patients for developing TMJ and patients currently suffering from TMJ related pain. It is important to educate patients about treatment options for TMJ including conservative management of symptoms provided by Physical therapists.





Authors:

Lake Washington Physical Therapy
Bob Cruikshank, PT, DPT
Ben Wobker, PT, MSPT, CSCS

References:
Orthopedic Physical Assessment, 4th Edition. David J. Magee, 2006. Millar, AL, et. al.
Epidemiological study of incidence of shoulder conditions. JOSPT, 36: 403-414, 2006
www.emedicine.medscape.com/article/92974-overview


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