From the Guidelines
Meckel's diverticulum is a congenital outpouching of the small intestine, specifically located on the antimesenteric border of the ileum, typically 2 feet (60 cm) proximal to the ileocecal valve. This condition results from incomplete obliteration of the vitelline duct (omphalomesenteric duct) during embryonic development. The anatomy of Meckel's diverticulum can be understood by considering the following key points:
- It is a true diverticulum, meaning it contains all layers of the intestinal wall (mucosa, submucosa, muscularis propria, and serosa) [no direct evidence from 1, but general medical knowledge].
- The blood supply to Meckel's diverticulum comes from a remnant of the vitelline artery, which branches from the superior mesenteric artery [no direct evidence from 1, but general medical knowledge].
- The presence of heterotopic gastric mucosa in about 50% of cases explains why peptic ulceration and bleeding are common complications, as this tissue secretes acid that can erode the adjacent ileal mucosa [no direct evidence from 1, but general medical knowledge].
- A Meckel scan can be performed to investigate for a Meckel diverticulum, which involves the intravenous administration of 99mTc pertechnetate, accumulating in gastric mucosa often found ectopically in a Meckel diverticulum 1. Meckel's diverticulum follows the "rule of 2s": it affects approximately 2% of the population, is commonly 2 inches (5 cm) in length, is typically found within 2 feet of the ileocecal valve, often becomes symptomatic before age 2, and contains 2 types of heterotopic tissue (gastric and pancreatic) [no direct evidence from 1, but general medical knowledge].
From the Research
Anatomy of Meckel's Diverticulum
Meckel's diverticulum is a congenital anomaly resulting from the incomplete obliteration of the omphalomesenteric duct during the 7th week of gestation 2. The diverticulum is usually located in the last 90 cm of the terminal ileum 3 and is formed by all layers of the small intestine.
Characteristics of Meckel's Diverticulum
Some key characteristics of Meckel's diverticulum include:
- It is the most common congenital abnormality of the small intestine 3, 4, 2
- It frequently contains heterotopic tissue, usually gastric mucosa 3
- The wall of Meckel's diverticulum consists of all layers typical of the small intestine 5
- It is usually approximately 2-3 cm long, but can reach lengths of over 10 centimeters 5
- It is usually set on a narrow base 5
Location and Variation
Meckel's diverticulum is classically located 2 feet proximal to the ileocecal valve 2 or approximately 60-100 cm away from the Bauhin's valve 5. Variations of this congenital malformation have been recorded based on location, size, and form 2.
Composition
The diverticulum may contain pancreatic tissue and oxyntic and antral type gastric mucosa, in addition to intestinal mucosa 3. This heterotopic tissue can lead to complications such as chronic peptic ulceration 3.