the greater omentum and loops of small bowel become adherent to the inflamed appendix, walling off the spread of peritoneal contamination and resulting in a phlegmonous mass or para- caecal abscess. Rarely, appendiceal inflammation resolves, leaving a distended mucus-filled organ termed a mucocele of the appendix. It is the potential for diffuse peritonitis that is the great threat of acute appendicitis. Peritonitis occurs as a result of free migration of bacteria through an ischaemic appendicular wall, frank perforation of a gangrenous appendix or delayed perforation of an appendix abscess.