The wrist contains a narrow passageway that leads from the wrist to the hand, known as the carpal tunnel. This tunnel is made of bones on the bottom with a ligament soft tissue roof.
The carpal tunnel houses the median nerve, which controls movement and feeling of the thumb and fingers, except for the pinky. In the tunnel are also flexor tendons, which allow you to bend your thumb and fingers.
Various conditions can cause irritation to the median nerve within the carpal tunnel, which can cause a host of symptoms including pain, weakness, and numbness in the fingers.