Medication, administered locally or regionally, which is used to eliminate pain in specific parts of the body, such as the area in which surgery is taking place: In local anesthesia, an agent is injected into the actual surgical site, while in regional anesthesia, the anesthetic agent is injected at a distance from the surgical site near the nerve that supplies that particular area.

The surgeon used a regional anesthesia when operating on Mike's foot, dulling the pain from his ankle and down to his toes.