(dysesthesia), weakness,loss of dexterity, and a sense of"swelling or perked circulation." Duration of symptoms varies from several days to years and may be continuous or intermittent. In chronic cases, trophic changes in the hand and ann may result in frank muscle atrophy and complete loss of movement Discomfort usually begins at a specific site and may radiate proximally and distally on the arm. Multiple nerves may become involved, ora single nerve may be compressed in more than one location (double crush syndrome). Compression of a peripheral nerve in one location may sensitize it, making it more susceptible to compression at another site.20

Evaluation of nerve entrapment syndromes
A thorough history must be obtained. Underlying metabolic disorders, such as diabetes, alcoholism, thyroid dysfunction, or rheumatoid disorders, must be elicited. A complete work history , related or not to performing arts, must be sought along with possible old acute trauma. The possibility of primary nerve disease or syringomyelia must not be forgotten. A comprehensive physical examination completes the initial evaluation.
In evaluating performingartists, one must see them in action. I have had musicians play for me in bathing or aerobic exercise attire to fully evaluate posture, position of the neck and shoulder girdle, and relative positions of both arms to the fingertips. If a specific set of movements brings on a symptom, I elicit this directly. I have patients exhibit a broad range of playing techniques. While I do not pretend to be a music instructor, I comment on specific techniques liable to cause muscle tendon strain or nerve compression. A thorough neurological exam includes evaluation of sensory and motor function, reflexes, and the presence or absence of pseudomotor signs, such as skin tone, color changes, sweat patterns, swelling, skin turgor, or rigidity. Sensory function is evaluated by testing sharp/dull perception, two-point discrimination, stereognosis, threshold light touch perception, static and moving two-point discrimination, and vibratory perception and position. Motor function is evaluated by testing specific muscles and muscle groups in the hand, forearm, elbow, upper arm, and neck.
There are a battery of provocative tests that increase the pressure across the particular fiber osseous tunnel one wishes to study. The Phalen's test involves passive wrist flexion at 90 degrees for 45 seconds for the median and ulnar nerve at the wrist. The elbow flexion test involves full supination and flexion of greater than 120 degrees for one minute for the cubital tunnel at the elbow. Supination against resistance or resisted middle finger extension tests for radial tunnel syndrome. One evaluates pronator syndrome by resisted finger flexion and forearm pronation with direct percussion over the anterior elbow. Dysesthesia caused by any of these maneuvers constitutes a positive exam. Tinel's test, involving direct percussion of the nerve at the area of possible compression, is less specific or sensitive. The thoracic outlet may be evaluated by Adson's test--the disappearance of the ipsilateral radial pulse when the involved arm is maximally elevated to shoulder level with the neck tilted and turned in the direction of the arm.