What is Temporomandibular Joint Disfunction?
Temporomandibular Joint Disfunction commonly referred to as TMJ, is a condition affecting the temporomandibular joint. The associated muscles, the associated structures and the joint itself can be involved in this disorder. The temporomandibular joint is located where the mandible (jawbone) meets the temporal bone of the cranium.
There are many possible causes for TMJ including stress, imbalances in the muscles of mastication (chewing), cranial bone misalignment, postural disfunction, joint pathology and trauma. “Three components must be present for TMJ disfunction to occur: predisposition, tissue alteration and stress.” “Predisposition can be intrinsic-the genetic development of muscles, ligaments and bones-or extrinsic-trauma to the neck, face or jaw. Tissue alteration can occur to the skeletal, dental and neuromuscular structures. Malocclusion, tooth loss, cranial bone misalignment, hypermobility, postural disfunction, spasm, ischemia, and trigger points are examples of tissue alteration. Stress results in increased tone of the muscles of mastication due to jaw clenching, bruxism (tooth grinding during sleep), or habits such as gum chewing.”
Common symptoms include a popping or clicking sound at the TMJ. This symptom by itself is not a sole indicator of TMJ disfunction. In some individuals this sound is a perfectly normal joint sound. Other symptoms include tenderness or pain and limited range of motion (opening of the mouth). Several tests should be conducted including Range of Motion Testing for the cervical spine and TMJ. A full range of motion testing should be conducted including passive, active free and active resisted isometric testing. Observations of either a “C” wobble or and “S” wobble will be observed with disfunction during active free testing. A “C” wobble indicates a capsular source while an “S” wobble indicates a muscular source.
Orthopedic tests for TMJ disfunction including the Three Knuckle Test should be conducted. The client attempts to place the knuckles from the middle three fingers of their non-dominant hand in their mouth. This test can identify a lack of range of motion indicating TMJ disfunction.