Carpal tunnel syndrome is a result of the compression of a nerve (median) due to inflammation within the carpal tunnel at the level of the wrist joint. It is characterized by pain, tingling, and in severe cases, numbness in the thumb, index, middle and half of the ring finger.

It is typically caused by repetitive tasks involving the hand and the wrist, for example typing with the wrists resting on hard surfaces with the wrist joints cocked (in extension). It is often worse at night or driving and in very severe cases can lead to a weak grip strength and decreased coordination. If left untreated it can progressively lead to atrophy of the thumb and finger muscles. Women are afflicted frequently more than men.

The main symptom of CTS is intermittent numbness of the thumb, index, long and radial half of the ring finger. The numbness usually occurs at night because we tend to sleep with our wrists flexed and is relieved by wearing a wrist splint that prevents flexion.