Referred pain and tender points.

A diffuse distribution of characteristic sites of tenderness is recognized to be a distinctive feature of the fibromyalgia/fibrositis syndrome, and is often associated with general symptoms such as exhaustion, stiffness, and irritability to external and internal stimuli. Equally important, and more common, is the development of similar tenderness at precisely the same sites in referred pain syndrome. The distribution of points is clumped, i.e., restricted to the appropriate region, and the general symptoms are lacking. The usual sites of origin are often unknown to the patient, because they lie deep in the cervical or lower lumbar spine. The clumped pattern of points is therefore very helpful in diagnosis and therapy.