omental

Omental is an anatomical adjective referring to the omentum, a peritoneal structure in the abdomen that forms two major folds: the greater omentum and the lesser omentum. The omentum connects the stomach with other abdominal organs and plays a role in fat storage, immune defense, and peritoneal organization. The term is often used in medical descriptions of diseases or surgical procedures involving the peritoneum.

The greater omentum hangs from the greater curvature of the stomach, drapes over the intestines, and attaches to the transverse colon. It is composed of four layers of peritoneum when unfixed and contains fat, vessels, and immune tissue. It is divided into ligaments: gastrocolic, gastrosplenic, and gastrophrenic. The lesser omentum extends from the lesser curvature and the proximal duodenum to the liver, containing the hepatogastric and hepatoduodenal ligaments; the latter transmits the portal triad.

Functions include fat storage and insulation, protection of abdominal viscera, and immune defense via macrophage-rich milky spots. The omentum can move within the peritoneal cavity to localize infection, seal perforations, and aid in healing. It also contributes to peritoneal fluid absorption and has a neuropathic innervation pattern from autonomic nerves.

Clinically, the omentum is involved in several conditions and procedures. Omental infarction or torsion are rare causes of abdominal pain. The omentum may be involved in peritoneal carcinomatosis, producing an omental cake on imaging. Omentectomy—surgical removal of all or part of the omentum—is performed in various oncologic surgeries and, in obesity, as part of certain procedures. Blood supply chiefly comes from the gastroepiploic arteries.