Expansion
A four-layered apron hanging from the greater curvature of the stomach
Mnemonic
“The abdominal policeman”, a four layered apron of peritoneum hanging from the greater curve of the stomach and folding back to the transverse colon.
Its functions follow the nickname:
- Walls off infection and perforation, limiting peritonitis
- Adheres to inflamed viscera, which is how an appendix mass forms
- Provides fat storage and immune tissue (milky spots)
- Used surgically as a vascularised patch to plug a perforation (Graham patch) or to buttress an anastomosis
It is a remnant of the dorsal mesogastrium, and its cavity, the inferior recess of the lesser sac, is usually obliterated in adults.
In children the omentum is short and thin, which is why perforation is less well localised and peritonitis more generalised than in adults.
Expansion
- Derived from the dorsal mesogastrium
- Hangs from the greater curvature of the stomach, descends in front of the small bowel, then folds back up to attach to the transverse colon
- Therefore has four layers of peritoneum
- Its upper part, between stomach and transverse colon, is the gastrocolic ligament
Functions:
- Walls off infection - it adheres to inflamed viscera and limits peritonitis, hence the “policeman of the abdomen”
- Fat storage and insulation
- Immune function, through milky spots containing macrophages
- Angiogenic - used surgically to buttress anastomoses and fill dead space
Its mobility is why an omental plug can seal a perforated duodenal ulcer, and why omental adhesions are so commonly encountered at repeat laparotomy.