Space-saving rule used in the Index, which is the last section of the annually published Current Procedural Terminology code book. For example:KneeIncision (of)In this example, the word in parentheses (of) does not appear in the Index, but it is inferred. As another example:PancreasAnesthesia (for procedures on)In this example, because there is no such entity as pancreas anesthesia , the words in parentheses are inferred (i.e., anesthesia for procedures on the pancreas).