Carpal tunnel syndrome is a painful illness of the hand and wrist. It is caused by a gradual compression of the median nerve. As the median nerve is squeezed, less blood and nutrients flow to it, causing pain, numbness, and weakness in the fingers and thumb. Most likely, the carpal tunnel syndrome is due to a congenital predisposition -- the carpal tunnel is simply smaller in some people than in others. However, the risk of developing carpal tunnel syndrome is especially common in those performing assembly line work.