Meckel diverticulum results from incomplete obliteration of which structure?

Meckel diverticulum results from incomplete obliteration of which structure?

• A. The vitelline (omphalomesenteric) duct
• B. The urachus
• C. The umbilical vein
• D. The dorsal mesentery

Answer: (A)

Meckel diverticulum arises when the vitelline (omphalomesenteric) duct fails to completely obliterate during embryonic development. This duct normally connects the yolk sac to the midgut early in gestation and should vanish by weeks 5–7. If a portion persists, it presents as a true diverticulum of the ileum, containing all layers of the intestinal wall. Clinically, it can harbor ectopic gastric mucosa (and sometimes pancreatic tissue), which may secrete acid and cause ulceration and painless lower GI bleeding in children, or lead to complications like obstruction or intussusception. The classic “rule of twos” helps remember features: about 2% of people, located roughly two feet from the ileocecal valve, about two inches long, often presenting before age two, and possibly containing two types of ectopic mucosa.

Meckel diverticulum arises when the vitelline (omphalomesenteric) duct fails to completely obliterate during embryonic development. This duct normally connects the yolk sac to the midgut early in gestation and should vanish by weeks 5–7. If a portion persists, it presents as a true diverticulum of the ileum, containing all layers of the intestinal wall. Clinically, it can harbor ectopic gastric mucosa (and sometimes pancreatic tissue), which may secrete acid and cause ulceration and painless lower GI bleeding in children, or lead to complications like obstruction or intussusception. The classic “rule of twos” helps remember features: about 2% of people, located roughly two feet from the ileocecal valve, about two inches long, often presenting before age two, and possibly containing two types of ectopic mucosa.