The lesser sac, also known as the omental bursa, is the cavity in the abdomen that is formed by the lesser and greater omentum. Usually found in mammals, it is connected with the greater sac via the omental foramen (previously known as the Foramen of Winslow). In mammals, it is common for the lesser sac to contain considerable amounts of fat.
- Anterior margin
- listed from the top-to-bottom margin: Quadrate lobe of the liver, lesser omentum, stomach, gastrocolic ligament
- Lateral margin
- listed from the most anterior to the most posterior margin: Gastrosplenic ligament, spleen, phrenicosplenic ligament
- Inferior margin
- Greater omentum
- Superior margin
If any of the marginal structures rupture their contents could leak into the lesser sac. If the stomach were to rupture on its anterior side though the leak would collect in the greater sac.
- Schematic figure of the bursa omentalis, etc. Human embryo of eight weeks.
- Diagrams to illustrate the development of the greater omentum and transverse mesocolon.
- Omental bursa
- Shahani RB, Bijlani RS, Dalvi AN, Shah HK, Samsi AB (1994). "Massive upper gastrointestinal haemorrhage due to direct visceral erosion of splenic artery aneurysm". J Postgrad Med. 40: 220–222.