A pinched nerve occurs when too much pressure is applied to a nerve by surrounding tissues such as bones, cartilage, muscles or tendons. This pressure disrupts the nerve's function, causing pain, tingling, numbness or weakness.
A pinched nerve can occur at several sites in your body. A herniated disk in your lower spine, for example, may put pressure on a nerve root, causing pain that radiates down the back of your leg (sciatica). Likewise, a pinched nerve in your wrist can lead to pain and numbness in your hand and fingers (carpal tunnel syndrome).