Actually called the Carpal Tunnel runs along the underside of your wrist and carries the complex system of nerves and muscles that control your hand and fingers and the sense of touch. Without it you wouldn't have use of your hand at all and in case of Carpal Tunnel Syndrome , its where the tunnel has been compromised to whatever degree and restricts feeling and control of the hand to a certain degree. A total collapse of the CT prohibits the hand to work and surgery is required to fix.
I shut mine off about 25 years ago and after several surgeries, a world council of DRs choose the best option for me was to install a steel plate 10 inches by 1 inch with titanium screws and fuse my left wrist straight so it could never bend again and Airport metal detectors do NOT sense this plate at all