The greater omentum is a part of the anatomy of the abdomen and consists of a prominent fold of peritoneum that hangs down from the stomach in front of the transverse colon to which it is attached. In animals, the greater omentum is called “caul”. The omentum is comprised of a double sheet of peritoneum made up of four layers. The function of the omentum is fat deposition, having varying amounts of adipose tissue, and plays a role in the immune system due to the presence of macrophages and isolation of wounds and infections. It may often be found wrapped around areas of infection and trauma.
Anatomy of the greater omentum
The two layers of the greater omentum that go down from the greater curvature of the stomach and the beginning of the duodenum pass in front of the small intestines.
In young subjects, it is easy to differentiate the two layers, but in adults the layers are more or less inseparably blended.
The greater omentum always contains some adipose tissue but is usually thin and has a perforated appearance. It is developed from the dorsal mesentery that attaches the stomach to the back of the abdominal wall and is made up of two main structures: the gastrocolic ligament (attaches to transverse colon) and gastrosplenic ligament (attaches to the spleen).
The greater omentum gets its blood supply from the right and left gastroepiploic vessels, with both ultimately originate in the celiac trunk (via the common hepatic artery and the splenic artery, respectively). The two blood vessels merge within the omentum along the greater curvature of the stomach.
Sometimes surgical removal of a portion of the greater omentum is necessary because of ovarian cancer or aggressive endometrial cancer that may have metastasized to the omentum. This procedure is called omentectomy and is a relatively simple procedure with no serious complications or side effects.