Myofascial trigger points in persistent posttraumatic shoulder pain.

Persistent pain and disability after injuries to the shoulder sometimes create a difficult diagnostic and therapeutic problem. In many such cases, myofascial trigger points seem to cause symptoms. Three cases in which pain had persisted for eight to 33 months after injury illustrate the manifestations of posttraumatic myofascial trigger point disorders. Trigger points are located by finding discrete foci of tenderness in muscles. Trigger points may be palpably firmer than surrounding muscle, forming nodules; they may twitch in response to palpation and may refer pain to a specific area when stimulated. Failure to recognize the myofascial source of pain can lead to erroneous diagnoses of articular, neurologic, or emotional disorder. Current pathophysiologic theories about trigger points may explain the persistence and topographic spreading of pain after muscular injuries. Appropriate treatment of myofascial trigger points can relieve chronic pain and disability.