**Question:** Meckel's diverticulum is remnant of -

**Core Concept:** Meckel's diverticulum is a vestigial structure found in the gastrointestinal tract, typically in the lesser sac of the abdomen. It is a blind-ended pouch derived from the embryonic vitelline duct.

**Why the Correct Answer is Right:** Meckel's diverticulum is a part of human anatomy that remains from our embryonic development. It is derived from the obliterated vitelline duct, which is a remnant of the yolk sac that normally regresses during fetal development. In humans, this structure fails to regress and remains as a blind pouch within the ileum, the terminal part of the small intestine.

**Why Each Wrong Option is Incorrect:**

A. **Option A:** Omental sac - This is not related to Meckel's diverticulum as it refers to the sac containing the greater omentum, which does not contribute to the development of Meckel's diverticulum.

B. **Option B:** Vitelline duct - While the vitelline duct is related to Meckel's diverticulum, the correct answer should mention the obliteration of the duct during embryonic development.

C. **Option C:** Omental bursa - This is another embryonic structure related to the omentum, but it does not explain the origin of Meckel's diverticulum.

D. **Option D:** Ovarian remnant - Meckel's diverticulum is derived from the vitelline duct, not the remnants of the ovary, which is unrelated to its formation.

**Clinical Pearl:** Meckel's diverticulum is a developmental anomaly that occurs in approximately 2% of the general population. Although generally benign, it can lead to complications like gastrointestinal bleeding, obstruction, or even malignant potential (rarely). Therefore, it is essential for medical students and healthcare professionals to be familiar with this developmental anomaly and its potential complications.

**Correct Answer:** D. Ovis (Option D) refers to the remnants of the ovary, which is not related to the development of Meckel's diverticulum. Meckel's diverticulum is derived from the vitelline duct, which is part of the embryonic midgut, unlike the remnants of the ovary.

**Clinical Pearls:**
1. Understanding the embryological origins of Meckel's diverticulum is crucial in understanding its potential complications and management strategies.
2. Meckel's diverticulum is a part of human anatomy that develops during embryonic life and persists into adulthood. A proper knowledge of this structure can help in diagnosing and treating complications associated with it.