Is the appendix where you think it is--and if not does it matter?

For over 100 years the recognized surface marking for the appendix has been McBurney's point (the junction of the lateral and middle thirds of a line joining the umbilicus with the right anterior superior iliac spine (ASIS)). In order to test its validity, the relationship between McBurney's point and the appendix was determined on 275 double contrast barium enemas (DCBE). A wide spread of distribution of the site of the appendix base was seen. Only 35% of appendix bases were found to lie within 5 cm of McBurney's point, and 15% were more than 10 cm distant. Seventy-five per cent of appendix bases were below and medial to a line joining the umbilicus with the right ASIS. These findings are in agreement with world-wide studies conducted by the World Organisation of Gastroenterology which showed that less than half of all patients with appendicitis have tenderness maximal over McBurney's point. A record was also made in 93 cases of the position of the appendix in relation to the caecum. The importance of these results in the diagnosis and management of patients with suspected appendicitis is discussed.