When you repeatedly move your fingers in the same pattern for hours on end, the tendons that connect your finger muscles to your wrist bones get irritated and inflamed. In turn, the ligaments that connect your wrist bones swell. The swollen tissues make for very tight accommodations inside the carpal tunnel, the channel deep inside your wrist where your finger tendons and wrist ligaments come together.

Within the narrow confines of that channel, the tissues press on an important and highly sensitive set of nerve fib ers called the median nerve. The median nerve controls sensation and movement in your hand. When the nerve is under pressure, you experience tingling, burning, or numbness in your hand-the classic symptoms of CTS.

Though computers are rightly blamed for the majority of CTS cases, the condition can result from any activity that involves constant, repetitive motion. Even if you're not married to a keyboard all day, you might begin to experience CTS symptoms if you do things like knitting, hammering, playing tennis or racquetball, or playing a musical instrument. CTS is also associated with tasks that deliver a steady vibration to the wrist, such as operating a jackhammer or other power tools. Another cause not commonly known is the repeated flexing of the wrist during sleep.

CTS can be aggravated by health problems that have nothing whatever to do with repetitive motion. For example, people with diabetes, rheumatoid arthritis, and thyroid problems sometimes develop classic CTS symptoms. Gender plays a role, too: You have a greater risk of developing CTS if you're a woman, because the condition is three times more common among women than among men. Female hormonal fluctuations during the menstrual cycle, pregnancy, and menopause make tissues inside the wrist swell more than usual, putting pressure on the median nerve. If pregnancy is behind the swelling, however, CTS symptoms may vanish after delivery, when hormone levels return to normal.

At first, CTS may affect only the thumb and first three fingers of the hand. (The pinkie is spared because it isn't controlled by the median nerve.) And sometimes it affects only the dominant hand, although more than half of all CTS cases involve both hands.

If you ignore the initial symptoms and continue engaging in a repetitive task, you can end up with constant pain in your hand and arm. In the most severe cases, CTS can permanently damage the hands, making repetitive tasks like keyboarding impossible.

Fortunately, CTS never has to progress to such an advanced stage. With prompt intervention on your part-and a few of the remedies listed below-you can quickly get the upper hand on CTS symptoms.