The relationship between dead arm syndrome and thoracic outlet syndrome.

A relationship exists between anterior shoulder subluxation and thoracic outlet syndrome that is responsible for the more florid symptoms of dead arm syndrome (DAS) in some patients. This relationship was demonstrated in eight of 27 patients (30%) in a consecutive series of Bankart operations for treatment of subluxation. The mechanism is associated with a disturbance in the kinesiology of the shoulder-joint complex that alters the position of the scapula relative to the rib cage and neurovascular supply to the upper limb. Therapy is directed toward restoration of the stability of the glenohumeral joint so that normal biomechanics can be reestablished. In advanced stages of thoracic outlet syndrome, however, DAS may initially require surgical decompression of the nerves and vessels. Careful attention to postural mechanics is essential for rational diagnosis and treatment of DAS.