The detailed anatomy of the muscles and fascial layers of the anterior abdominal wall is described in Chapters 39, 40, 41 and 42. Peritoneal lavage is the first procedure illustrated in this section because it is often the first “laparotomy” performed by the junior resident or student. The general topography of the abdominal cavity is introduced in Chapter 39. The relationships of the viscera and a method for systematic exploration of the abdominal cavity, with considerations for trauma laparotomy, are described in Chapters 41 and 42. Additional information on the lateral abdominal wall may be found in the chapters on colon resection (Chapter 81), cholecystectomy (Chapter 63), and appendectomy (Chapter 76), in which special abdominal incisions are described.