The appendix is located in the lower right quadrant of the abdomen, or more specifically, the right iliac fossa. It averages 10 cm in length, but can range from 2 to 20 cm. The diameter of the appendix is usually between 7 and 8 mm. The human appendix is a vestigial structure which does absolutely nothing for the body. Given the appendix's propensity to cause death via infection, and the general good health of people who have had their appendix removed or who have a congenital absence of it, the appendix appears to have no function in the human body.