Activities that require repetitive flexing and extending of tendons in the hands and wrists, especi...
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Activities that require repetitive flexing and extending of tendons in the hands and wrists, especially over long periods, are a common cause of the condition known as carpal tunnel syndrome. The carpal tunnel is a narrow, rigid passageway of ligaments and bone on the palm side of your wrist. It protects the tendons that bend your fingers and the median nerve, which run from your forearm into your hand. The median nerve provides sensation to your thumb; index and middle fingers; and the inside half of your ring finger. It also provides signals that enable the fingers and thumb to move. Pressure on the nerves can cause numbness, pain, and weakness in the hand and wrist that radiates up the arm. The pressure can result from anything that reduces space for the nerves in the carpal tunnel. For example, the lining of the tunnel may swell if it becomes inflamed. Or the tendons may become swollen. And some people have a tunnel that is narrower than normal.