Carpal = The wrist
Tunnel = A space at the front of your wrist
Syndrome = A collection of symptoms, (i.e.: wrist, hand thumb or finger pain, tingling, numbness) and signs, (physical findings such as muscle weakness or loss of sensation in the hand, thumb or fingers)
What is missing from this description is any mention of the nerve structure inside the carpal tunnel which produces the symptoms, namely the median nerve. This nerve is the most commonly irritated nerve in the arm. Typically, it is more likely to occur in females, usually in young adults to middle age and associated with repetitive hand use such as typing, mousing or manual work. Diabetic patients are at greater risk, and those who are pregnant.
Once the median nerve gets irritated you may experience wrist pain or hand pain, tingling or numbness in the palm of your hand or into the front of the thumb, index, middle or ring finger. The symptoms are typically made worse with hand usage and are more noticeable at night, which often disturbs sleep. The sensations that you feel are caused by irritation of that part of the nerve that tells your brain about sensation. On the other hand (no pun intended!) the nerve also has motor fibers which send messages to make your muscles work. If these are affected, weakness of the thumb may be noticed.