A nerve block injection is a nerve-numbing medication that is injected in a specific area of the body to relieve or manage pain, states WebMD. Groups of nerves are called a ganglion, or a plexus, and can cause pain in a certain area of the body.
There are different types of nerve blocks that are used for different purposes, according to WebMD. A therapeutic nerve block is used to treat acute or chronic pain, while a diagnostic nerve block is used to find the cause of pain. Preemptive nerve blocks are used to treat pain before it occurs, such as phantom limb pain after an amputation.