Carpal tunnel syndrome results from compression and irritation of the median nerve where it passes through the wrist. In the end, the median nerve is responsible for both sensation and movement. When the median nerve is compressed, an individual's hand will feel as if it has "gone to sleep." The individual will experience numbness, tingling, and a prickly pin like sensation over the palm surface of the hand, and the individual may begin to experience muscle weakness, making it difficult to open jars and hold objects with the affected hand. Eventually, the muscles of the hand served by the median nerve may begin to atrophy, or grow noticeably smaller.

Compression of the median nerve in the wrist can occur during a number of different conditions, particularly conditions that lead to changes in fluid accumulation throughout the body. Because the area of the wrist through which the median nerve passes is very narrow, any swelling in the area will lead to pressure on the median nerve, which will interfere with the nerve's ability to function normally. Pregnancy, obesity, arthritis, certain thyroid conditions, diabetes, and certain pituitary abnormalities all predispose to carpal tunnel syndrome. Furthermore, overuse syndrome, in which an individual's job requires repeated strong wrist motions (in particular, motions which bend the wrist inward toward the forearm) can also predispose to carpal tunnel syndrome.

Research conducted by the American Academy of Orthopaedic Surgeons has found that advanced carpal tunnel syndrome can be prevented in many cases. They concluded that by doing an uncomplicated set of wrist exercises consistently before work, during breaks, and after work, pressure on the median nerves that leads to carpal tunnel syndrome can be avoided. The exercises are simple, involving mild flexion and extension of the wrists. By stretching the associated tendons, trauma from repetitive exertion is made less likely by significantly lowering pressure within carpal tunnels. People most likely to benefit from such exercise are those who use computers and other electronic keyboard devices daily. Women are known to experience carpal tunnel syndrome more frequently than do men.

Carpal tunnel syndrome is initially treated by splinting, which prevents the wrist from flexing inward into the position that exacerbates median nerve compression. When carpal tunnel syndrome is more advanced, injection of steroids into the wrist to decrease inflammation may be necessary. The most severe cases of carpal tunnel syndrome may require surgery to decrease the compression of the median nerve and restore its normal function.

An often underestimated disorder, carpal tunnel syndrome affects significant numbers of workers. In some years, according to federal labor statistics, carpal tunnel syndrome exceeded lower back pain in its contribution to the duration of work absences. One estimate reports that as many as 5-10 workers per 10,000 will miss work for some length of time each year due to work-related carpal tunnel syndrome. Additionally, the affliction is not limited to those whose jobs involve long hours of typing. International epidemiological data indicate that the highest rates of the disorder also include occupations such as meat-packers, automobile and other assembly workers, and poultry processors. Also from these studies, strong evidence is presented which positively correlates carpal tunnel syndrome with multiple risk factors, rather than a single factor alone. It is believed that the risk of developing carpal tunnel syndrome is far greater when continual repetition of action is combined with increased force of the action, wrist vibration, and overall poor posture.

Record Number: A30421552

SOURCE:
Carpal tunnel syndrome. Gale Encyclopedia of Science.  June 2001 pNA.

Full Text: COPYRIGHT 2001 Gale Group