Ans is 'c' i.e., Arises at the Mesentric border Meckel's diveiculum is situated at the anti-mesenteric border of small intestine. Meckel's diveiculum is a true diveiculum as it has all the 3 layers of the intestine. It's the most common congenital anomaly of the gastrointestinal tract. Male to female ratio is 3 : 2. Approximately 60% of Meckel's diveicula contain heterotopic mucosa, of which more than 60% consists of gastric mucosa. Second most common ectopic mucosa is that of Pancreas (Pancreatic acini). Other mucosa are -colonic mucosa, Brunner's gland, pancreatic islets, endometriosis and hepatobiliary tissue. A useful but crude Mnemonic used traditionally for describing Meckel's diveicula is Rule of two : i.e. - 2% prevalence - 2 inch in length - 2 feet proximal to ilcocecal valve. half of these who are symptomatic are younger than 2 yrs of age Meckel's diveicula are asymptomatic. Symptoms arise only when any complication occurs. Complications Most common complication in children & young adults (< 18 yrs of age) --> bleeding in adults --> intestinal obstruction overall --> bleeding Following complications are noted in Meckel's diveiculum. (1) Bleeding - bleeding in Meckel's diveiculum is usually the result of ulceration in ileal mucosa adjacent to the diveiculum caused by the acid secreted by heterotopic gastric mucosa within the diveiculum. (2) Intestinal obstruction Intestinal obstruction associated with Meckel's diveiculum can result from several mechanisms. a) Volvulus of the intestine around the fibrous band attaching the diveiculum to the umbilicus b) Intussusception with the diveiculum acting as the lead point. c) Entrapment of intestine by a mesodiveicular band (Mesodiveicular band is a remnant of left vitelline aery, it tethers the Meckel's diveiculum to the ileal mesentry.) d) Stricture secondary to chronic diveiculitis. (3) Diveiculitis - clinical picture is similar to appendicitis. - diveiculitis may lead to perforation. Littre's hernia - rarely Meckel's diveiculum is found in inguinal or femoral hernia. This is known as Littre's hernia. Diagnostic studies Meckel's diveiculum in the absence of bleeding can be rarely diagnosed before surgical intervention. Barium meal follow through can rarely demonstrate the diveiculum. Barium enteroclysis can demonstrate the diveicula in 75% of cases but is avoided during acute presentation of complication. If repeated episodes of lower GI bleed occur and an ectopic gastric mucosa in the Meckel's diveiculum is suspected, it can be demonstrated by Technetium" peechnate radionuclide scan. It demonstrates the ectopic gastric mucosa and localizes the Meckel's diveiculum. Angiography can localize the site of bleeding during acute hemorrhage related to meckel's diveicula.