Carpal tunnel syndrome is a condition that involves the compression of the median nerve within the hand, as it passes through the space in the wrist. The median nerve can be found on the palm side of the hand, and the space through which it has to pass is called the carpal tunnel. It’s this nerve that provides sensation throughout your index finger, thumb, part of the ring finger, and your longest, middle finger. Carpal tunnel syndrome can occur in either hand, and it’s caused by swelling within the wrist that leads to compression. Often, that compression causes numbness, tingling, weakness, and other issues on the side of your hand.