Occupational musculoskeletal stress and disorders of the neck and shoulder: a review of possible pathophysiology.

Disorders and complaints in the neck and shoulder regions are common among industrial workers and are often attributed to occupational musculoskeletal stress. The possible pathophysiological mechanism of occupational stress on the neck and shoulders is reviewed. A mechanical origin for cervical disc degeneration and osteoarthrosis is reported for a few occupational groups. However, a mechanical origin for osteoarthrosis is debatable. A work posture involving elevated arms may accelerate degeneration of shoulder tendons through impairment of circulation due to static tension and humeral compression against the coracoacromial arch. Furthermore, work tasks with repetitive arm movements may evoke shoulder tendinitis or tendo-vaginitis, probably due to friction. Three possible routes to neck-shoulder muscular pain are discussed; mechanical failure, local ischemia and energy metabolism disturbance.