Below is a narrated animation of TMJ and Myofascial Pain Syndrome . Click here to license this video on Alila Medical Media website.

The temporomandibular joint

The temporomandibular joint – the TMJ – is the joint between the lower jawbone – the mandible – and the temporal bone of the skull. The TMJ is responsible for jaw movement and enables chewing, talking and yawning. Temporomandibular disorders, or TMD, refer to a group of conditions characterized by pain in the jaw area and limited movement of the mandible. TMD may be caused by problems in the joint itself or in the muscles surrounding the joint. Problems in the joint include: arthritis, inflammation and internal derangements. When the problem is in the muscles, the condition is called myofascial pain syndrome.

Myofascial pain syndrome

Myofascial pain syndrome is very common and can occur in patients with a normal temporomandibular joint. The syndrome is characterized by presence of hyperirritable spots located in skeletal muscles called trigger points. A trigger point can be felt as a nodule of muscle with harder than normal consistency. Palpation of trigger points may elicit pain in a different location. This is called referred pain.

Fig. 1: Muscles of mastication (chewing muscles). Click on image to see it on Alila Medical Media website where the image is also available for licensing.