What Causes Carpal Tunnel Syndrome?

Carpal Tunnel Syndrome (CTS) is a condition in which abnormal pressure is placed on the median nerve, which runs through the carpal tunnel. The carpal tunnel, located in the middle of the wrist, is formed by bones and a ligament. In addition to the median nerve, the carpal tunnel also contains tendons.

The abnormal pressure may be due to any of several possible causes. The most common causes are simple wear and tear due to overuse or the effects of aging, or a previous wrist injury, such as a fracture.

Carpal tunnel syndrome is common, affecting 0.1% of the general population, and as many as 15% of workers in high-risk industries, such as electronic parts assemblers, musicians, and dental hygienists. Although the use of highly repetitive wrist movements appears to be correlated with the development of carpal tunnel syndrome, other factors, such as medical conditions like diabetes, rheumatoid arthritis, thyroid disease, and pregnancy may be even more important. Nonetheless, the incidence rises with increasing repetition of hand use (such as typing), and by a high level of force with each motion, (such as meat packers), in whom the incidence of carpal tunnel syndrome has been reported as high as 15%

Over time, pressure on the median nerve causes numbness, tingling and discomfort in some or all of the fingers in the affected hand. Some people with CTS experience pain in other parts of the hand, or even in the lower arm. These symptoms usually become progressively worse, and hand strength may diminish. Without treatment, the median nerve may suffer permanent damage.

Good ergonomics in the workplace can lower an employee's risk of developing CTS. The ideal work station for a computer operator would have a chair with adjustable seat height and back rest, with the chair on wheels for ease in movement. Arm rests are often helpful. Wrists should rest comfortably on the table in front of the keyboard. Use of a padded wrist rest will help keep the wrists in a neutral position, that is, minimally bent either laterally or vertically, thus obviating the need for the wrist bending that appears to be a common cause of CTS among computer operators.

Resting the sore area prevents further injury while allowing time to heal. Pain with activity is a sign that irritation is occurring. Try to avoid movements and activities that increase pain.

Ice decreases the size of blood vessels in the sore area, slowing inflammation and relieving pain. Choices of application include cold packs, ice bags, or ice massage. Ice massage is an easy and effective way to provide first aid. To try ice massage, simply freeze water in a paper cup. When needed, tear off the top inch, exposing the ice. Rub three to five minutes around the sore area until it feels numb.

Heat enlarges blood vessels, increasing blood in the area. This aids in flushing painful chemicals away from the sore area, while bringing in nutrients and oxygen. Heat also prepares tissue to be stretched by making the area more pliable. Real heat in the form of a heating pad, warm shower, or warm bath is more beneficial than creams that give the feeling of warmth.

Rubbing across a sore area may assist in the healing process. It increases the blood flow in the area, which brings nutrients and oxygen, while flushing out chemicals that cause pain. It also decreases pain by stimulating nerve pathways that "override" pain. By providing a rubbing action, one theory holds that new collagen fibers are aligned along lines of stress, strengthening the underlying tissue. Imagine a pile of toothpicks haphazardly lying in a pile. When you begin rubbing them in one direction, what happens? They line up. Your therapist should direct you where and in which direction to rub.

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