Tenderness at motor points: an aid in the diagnosis of pain in the shoulder referred from the cervical spine
C. C. Gunn MA MB BChir and W. E. Milbrandt MD
Journal of the American Osteopathic Association

ABSTRACT
Cervical spondylosis, a universal degenerative condition, often is misdiagnosed, because it causes no symptoms unless it impinges on pain-sensitive tissues or a nerve root to cause radiculitis and consequently is difficult to detect in early stages. It is possible to recognize neuropathy, however, by the presence of tenderness at motor points, since spondylotic pain may be transmitted via the segmental nerve to the corresponding myotome and felt as muscle pain and tenderness, which may be elicited easily at the motor point. In a combination prospective/retrospective study of 407 patients with primary shoulder pain, 50 patients who showed no obvious physical signs required electromyography for definitive diagnosis. Observations of tender motor points in these patients are compared with the medical records of the remaining 357 patients. Tender motor points were always found in patients with cervical spondylosis and shoulder pain, but absent in patients with extrinsic shoulder pain unless accompanied by concurrent spondylosis.

The "frozen shoulder" is not restrained by "capsulitis"; all movements are restricted because of muscle shortening.