Although local anesthesia usually is used in surgical procedures, field or nerve blocks can provide more effective anesthesia in some situations. In a field block, local anesthetic is infiltrated around the border of the surgical field, leaving the operative area undisturbed. In field blocks, epinephrine may be added to the anesthetic to enhance vasoconstriction and prolong the duration of anesthesia. In a nerve block, anesthetic is injected directly adjacent to the nerve supplying the surgical field. A review of regional anatomy and the location of nerves and other important structures is essential before administering the injection. Systemic toxicity is rare with regional anesthesia and can be prevented by using the smallest dose possible and aspirating before the injection. Supraorbital, supratrochlear, infraorbital, and mental nerve blocks can provide adequate anesthesia in procedures on parts of the face. Field block also may be considered when operating on the ear or lips.