Carpal tunnel syndrome

Carpal tunnel syndrome is the set of symptoms and signs that result from compression of the median nerve where it passes through the carpal tunnel of the wrist. Most cases are idiopathic, meaning no cause is known, although bleeding, swelling or deformity after a wrist fracture and the enlarged tendon linings of rheumatoid arthritis can also compress the nerve. The main symptoms are numbness and tingling of the thumb, index finger, middle finger and the thumb side of the ring finger, with pain in the hand and fingers that is usually worst at night. Left untreated for years to decades, it can cause loss of sensitivity, weakness and shrinkage of the thenar muscles at the base of the thumb. Work-related factors such as vibration, wrist extension or flexion, hand force and repetitive strain are recognized risk factors.