Most people's hands briefly "fall asleep" every now and then. The hand then feels numb or tingly. Although this is unpleasant, it's usually over very quickly. Carpal tunnel syndrome has similar symptoms – but they keep coming back again and are often painful.
The carpal tunnel is a passageway inside the wrist that is surrounded by bones and connective tissue. It is located on the inner side of the wrist at the base of the hand, and is covered by a strong, fibrous band made up of connective tissue, called the transverse carpal ligament. Tendons and the median nerve run through the carpal tunnel. This nerve is responsible for sensation and movement in the ball of the thumb and some parts of the hand. If the tissue inside the carpal tunnel swells up, it can push against the median nerve, which is what causes carpal tunnel syndrome. The symptoms often go away on their own, but they can sometimes last for quite a long time. Various treatments can provide relief.