A nerve block is a type of injection used to manage or prevent pain. A doctor may use ultrasound, a CT scan, or other imaging to figure out where to give a nerve block, and will then inject a pain-relieving or anti-inflammatory drug near the nerve. This will block pain signals and reduce pain in the area.
An epidural, used during labor and delivery, is a common type of nerve block, but there are many others. Nerve blocks can be surgical, in which certain nerves are cut or destroyed to block pain signals, or non-surgical, in which an injection can be given around the spinal cord or the nerve causing pain.