Carpal Tunnel

Bounded by bones and ligaments, the carpal tunnel is a narrow passageway — about as big around as your thumb — located on the palm side of your wrist. This tunnel protects a main nerve to your hand and nine tendons that bend your fingers. Pressure placed on the nerve produces the numbness, pain and, eventually, hand weakness that characterize carpal tunnel syndrome.

The cause of carpal tunnel syndrome is pressure on the median nerve. The median nerve is a mixed nerve, meaning it has a sensory function and also provides nerve signals to move your muscles (motor function). The median nerve provides sensation to your thumb, index finger, middle finger and the middle-finger side of the ring finger. Pressure on the nerve can stem from anything that reduces the space for it in the carpal tunnel. Causes might include anything from bone spurs to the most common cause, which is swelling or thickening of the lining and lubricating layer (synovium) of the tendons in your carpal tunnel.

Carpal tunnel syndrome typically starts gradually with a vague aching in your wrist that can extend to your hand or forearm. Other common carpal tunnel syndrome symptoms include: Tingling or numbness in your fingers or hand, especially your thumb, index, middle or ring fingers, but not your little finger. This sensation often occurs while driving a vehicle or holding a phone or a newspaper or upon awakening. Many people "shake out" their hands to relieve their symptoms. Pain radiating or extending from your wrist up your arm to your shoulder or down into your palm or fingers, especially after forceful or repetitive use. This usually occurs on palm side of your forearm. A sense of weakness in your hands and a tendency to drop objects as well a constant loss of feeling in some fingers this can occur if the condition is advanced.