A nerve block is a local anesthetic injected into or around a nerve or into the spine to temporarily prevent the nerve from relaying pain. A nerve block may cause temporary muscle paralysis or a loss of all feeling in the affected area or in the surrounding area.

Nerve blocks can be used to determine the source of pain, to treat painful conditions, and to predict how pain will respond to long-term treatments. Nerve blocks are also used for short-term pain relief after some surgeries and other procedures. They may be used for anesthesia during some smaller procedures, such as finger surgery.