Blocks are injections of medication onto or near nerves.
The medications that are injected include local anesthetics, steroids, and opioids. In some cases of severe pain it is even necessary to destroy a nerve with injections of phenol, pure ethanol, or by using needles that freeze or heat the nerves. Injections into joints are also referred to as blocks. Although not technically correct, such shorthand is commonly used. 1.Blocks with local anesthetic can be used to control acute pain.