Condition · Hand

Carpal tunnel syndrome

The median nerve reaches your hand through a tunnel at the wrist, roofed by a stiff band of tissue and shared with nine tendons. When the tunnel's contents are irritated and swollen, the nerve is the softest thing in there, so it complains first — numbness and tingling in the thumb, index and middle fingers, classically worst at night, and eventually a thumb pad that weakens and wastes. The tunnel is where the symptoms are, but the load usually starts further up the chain: sustained gripping without support from the elbow and shoulder.