Meckel's diverticulum. Small intestine affected by Meckel's diverticulum. This is a congenital abnormality characterised by a pouch (upper right) protruding from the wall of the small intestine. It is a vestigial remnant of the omphalomesenteric duct (also called the vitelline duct or yolk stalk). It is a common deformity, occurring in as many as 2% of the population. In most cases the diverticulum causes no problems, but it may lead to internal bleeding in children, and a blocked intestine in adults. The latter can cause severe abdominal pain, vomiting and swelling. If the diverticulum causes problems it can be surgically removed.