Corpus: Greater omentum
from Latin: omentum - net
1. Definition
The greater omentum is a fatty, double-layered fold of peritoneum formed by the fusion of the dorsal mesogastrium during embryonic development.
2. Anatomy
The greater omentum hangs like an apron from the large curvature of the stomach or from the transverse colon. It originates at the transverse colon's omental tenia and drapes over the front of the abdominal organs, particularly the small intestine, reaching approximately to the level of the navel (umbilicus). On the left, it transitions into the gastrosplenic ligament. It is well-vascularized and contains numerous lymphatic vessels.
The greater omentum can be divided into several sections:
- Gastrocolic ligament: Connects the large curvature of the stomach to the transverse colon.
- Gastrophrenic ligament: Extends between the gastric fundus and the diaphragm.
- Gastrosplenic ligament: Connects the large curvature of the stomach to the splenic hilum.
- Splenorenal ligament: Connects the anterior surface of the left kidney to the splenic hilum.
- Spleocolic ligament: Links the splenic hilum to the left colonic flexure.
2.1. Vascular supply
The greater omentum is supplied by an anastomosis between the right gastroepiploic artery (from the gastroduodenal artery of the common hepatic artery) and the left gastroepiploic artery (from the splenic artery).
3. Functions
The greater omentum has three main functions:
3.1. Immune defence
The greater omentum contains many macrophages and lymphocytes, allowing it to respond to inflammation in the abdominal cavity by covering and isolating the inflamed area, helping to prevent the spread of infection and peritonitis.
3.2. Regulation of the fluid balance
With its large surface area, the greater omentum plays a key role in regulating fluid balance in the peritoneal cavity by absorbing and releasing peritoneal fluid.
3.3. Fat storage
It serves as a major fat storage site, and in obese individuals, it can develop into a fat layer several centimeters thick.
see also: lesser omentum
4. Trivia
Due to its role in protecting the abdominal organs, the greater omentum is sometimes referred to as the "abdominal policeman."