Meckel's diverticulum is the most common congenital anomaly of the gastrointestinal tract. It results from incomplete obliteration of the vitelline duct leading to the formation of a true diverticulum of the small intestine . Meckel’s diverticula are uncommon and often clinically silent, particularly in the adult. Asymptomatic Meckel’s diverticulum may be discovered during abdominal exploration for the evaluation of unrelated pathology. Less commonly, they are found incidentally on diagnostic imaging. When symptomatic, Meckel’s diverticulum may present with abdominal pain or symptoms of gastrointestinal bleeding or bowel obstruction.
The embryology, clinical features, diagnosis and treatment of Meckel’s diverticulum are reviewed here. The clinical evaluation of various gastrointestinal symptoms (abdominal pain, gastrointestinal bleeding, bowel obstruction) in children and adults is found in separate topic reviews. General considerations for the management of other congenital anomalies of the gastrointestinal tract are reviewed elsewhere. (See "Intestinal malrotation".)
ANATOMY AND EMBRYOLOGY
Meckel's diverticulum is a true diverticulum, containing all layers of the small bowel wall. They arise from the antimesenteric surface of the middle-to-distal ileum. The diverticulum represents a persistent remnant of the omphalomesenteric duct, which connects the midgut to the yolk sac in the fetus. The normal development of the intestine is discussed elsewhere. (See "Overview of the development of the gastrointestinal tract".)
The omphalomesenteric duct normally involutes between the fifth and sixth weeks of human gestation as the bowel settles into its permanent position within the abdominal cavity. The persistence of the omphalomesenteric duct beyond fetal development may result in a variety of anatomic patterns (figure 1), including omphalomesenteric cysts, omphalomesenteric fistulae that drain through the umbilicus, and fibrous bands from the diverticulum to the umbilicus that predispose to bowel obstruction [2,3]. The most common form is a diverticulum without additional attachment, commonly referred to as Meckel's diverticulum . The rich blood supply to the diverticulum is provided by the vitelline artery, which is a branch of the superior mesenteric artery (figure 2). The embryological origin of the ectopic tissue within the walls of the diverticulum is not known; theories include a local erroneous association between neural crest and endodermal tissue and a missing restrictive mesodermal effect on the local endoderm within the diverticulum.
Meckel's diverticulum is the most common congenital malformation of the gastrointestinal tract . There is probably no familial predisposition for Meckel's diverticulum, although a few cases of occurrence within the same family have been reported . The prevalence of Meckel's diverticulum is increased in children born with major malformation of the umbilicus, alimentary tract, nervous system, or cardiovascular system, in descending order .