Carpal tunnel syndrome occurs when the median nerve, which runs from your forearm through your hand, is injured. The nerve runs through a very narrow area of the wrist called the carpal tunnel. Because the area is so narrow, it is very easy for the nerve to become compressed and damaged. This leads to the symptoms of carpal tunnel.
The median nerve provides sensation to the index and middle finger, as well as the thumb. This is why symptoms of carpal tunnel include pain and numbness in these areas.