Meckel’s diveiculum is a derivative of
**Core Concept**
Meckel's diverticulum is a congenital anomaly of the small intestine, resulting from the incomplete closure of the vitelline duct. It is a true diverticulum, containing all layers of the intestinal wall. The vitelline duct is a structure that connects the yolk sac to the intestinal tract during embryonic development.
**Why the Correct Answer is Right**
The vitelline duct typically obliterates and disappears by the 6th week of gestation. However, in some cases, it fails to close completely, leading to the formation of a Meckel's diverticulum. This diverticulum usually contains ectopic gastric or pancreatic tissue, which can cause symptoms due to acid production or enzyme secretion. The presence of ectopic tissue within the diverticulum is a hallmark of Meckel's diverticulum.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because Meckel's diverticulum is not derived from the omphalomesenteric duct, which is a different embryological structure.
**Option B:** This option is incorrect because Meckel's diverticulum is not derived from the ileal portion of the small intestine, although it is most commonly found in the ileum.
**Clinical Pearl / High-Yield Fact**
A Meckel's diverticulum can cause gastrointestinal bleeding, especially in children, due to the presence of ectopic gastric mucosa. It is essential to consider Meckel's diverticulum in the differential diagnosis of lower gastrointestinal bleeding, especially when other causes have been ruled out.
**Correct Answer: C. Vitelline duct.**