[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Gastrointestinal tract](https://durgical.com/en/general-pathology/areas/gi/) › Meckel diverticulum, and true vs false diverticula

# Meckel diverticulum, and true vs false diverticula

- Lesion

A small pouch left over from the yolk-sac duct sits on the ileum; it can bleed, block the bowel or mimic appendicitis.

Updated Nov 12, 2026

## Key points

- True diverticulum (all three layers of the wall) on the antimesenteric border of the ileum.
- Rule of twos: about 2 % of people, within about two feet of the ileocaecal valve, about two inches long, twice as common in males, often symptomatic by age two.
- Only a small minority ever cause symptoms.
- Ectopic gastric mucosa causes painless rectal bleeding in a child; ectopic pancreas may also be present.
- Most other diverticula (sigmoid, Zenker) are false: mucosa and submucosa herniate through the muscle.

## What it is

Meckel diverticulum is the commonest congenital anomaly of the gut and the classic true diverticulum: a blind pouch that keeps all layers of the bowel wall. It forms when the vitelline (omphalomesenteric) duct, which links the embryonic gut to the yolk sac, fails to involute. Most cause no trouble; when they do, it is usually because ectopic gastric mucosa in the pouch secretes acid and ulcerates the ileum beside it.

## Structure

- A solitary finger-like pouch on the antimesenteric side of the distal ileum.
- Wall: mucosa, submucosa and muscularis propria, like the normal bowel.
- Lining: small-bowel mucosa, sometimes with islands of gastric (acid-secreting) or pancreatic tissue.
- Peptic ulcer in the adjacent ileal mucosa when gastric tissue is present.

## True vs false diverticula

| Feature | True diverticulum | False (pseudo-) diverticulum |
| --- | --- | --- |
| Wall | All layers, including muscularis propria | Mucosa and submucosa only, through a gap in the muscle |
| [Origin](https://durgical.com/en/conditions/meckel-diverticulum/) | Usually congenital | Acquired, from raised pressure |
| [Examples](https://durgical.com/en/conditions/diverticular-disease-and-diverticulitis/) | Meckel diverticulum; the appendix itself | Sigmoid diverticula, Zenker, epiphrenic diverticula |

## Clinical notes

- Painless bright or dark rectal bleeding in a young child: think of ectopic gastric mucosa.
- Inflammation (Meckel diverticulitis) mimics acute appendicitis.
- The pouch can act as the lead point of an intussusception or twist the bowel (volvulus).

## In the lab

- A technetium-pertechnetate scan picks up the ectopic gastric mucosa.

## Memory aid

A forgotten cord from the yolk sac: a whole-wall pouch with a stomach inside it.

## Test yourself

Think of the answer, then tap the question to see it.

## Why is Meckel diverticulum called a true diverticulum?

Its wall contains all the layers of the bowel, including the muscularis propria.

## Which embryonic structure fails to involute in Meckel diverticulum?

The vitelline (omphalomesenteric) duct that joined the midgut to the yolk sac.

## What causes bleeding from a Meckel diverticulum?

Acid from ectopic gastric mucosa in the pouch ulcerates the adjacent ileal mucosa.

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## Elsewhere in DurgiPedia

- [Meckel diverticulum and other vitelline duct remnants](https://durgical.com/en/embryology/meckel-diverticulum-and-other-vitelline-duct-remnants/)
- [Midgut: physiological herniation and rotation](https://durgical.com/en/embryology/midgut-physiological-herniation-and-rotation/)

## Connections

## Related 5

- [Congenital anomalies of the gut](https://durgical.com/en/general-pathology/congenital-anomalies-of-the-gut/)
- [Sigmoid diverticular disease](https://durgical.com/en/general-pathology/sigmoid-diverticular-disease/)
- [Peptic ulcer](https://durgical.com/en/general-pathology/peptic-ulcer/)
- [Acute appendicitis](https://durgical.com/en/general-pathology/acute-appendicitis/)
- [Intestinal obstruction](https://durgical.com/en/general-pathology/intestinal-obstruction/)

## Related conditions 6

- [Meckel diverticulum](https://durgical.com/en/conditions/meckel-diverticulum/)
- [Zenker diverticulum (pharyngo-oesophageal diverticulum)](https://durgical.com/en/conditions/zenker-diverticulum/)
- [Diverticular disease and diverticulitis](https://durgical.com/en/conditions/diverticular-disease-and-diverticulitis/)
- [Lower gastrointestinal bleeding](https://durgical.com/en/conditions/lower-gastrointestinal-bleeding/)
- [Acute appendicitis](https://durgical.com/en/conditions/acute-appendicitis/)
- [Intussusception (children)](https://durgical.com/en/conditions/intussusception/)

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Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Meckel diverticulum: MedlinePlus Medical Encyclopedia](https://medlineplus.gov/ency/article/000234.htm) (MedlinePlus, US National Library of Medicine, 2025).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/general-pathology/meckel-diverticulum-and-true-vs-false-diverticula/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/meckel-diverticulum-and-true-vs-false-diverticula/