Lesser sac

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Lesser sac
Latinbursa omentalis
Anatomical terminology

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 not uncommon for the lesser sac to contain considerable amounts of fat.

Anatomic margins[edit]

Anterior margin, named from the top-to-bottom margin:

Quadrate lobe of the liver, lesser omentum, stomach, gastrocolic ligament

Lateral margin, named from the most anterior to the most posterior margin:

Gastrosplenic ligament, spleen, phrenicosplenic ligament

Posterior margin:

Left kidney and adrenal gland, pancreas

Inferior margin:

Greater omentum

Superior margin:

Liver [1]

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.[citation needed]

The lesser sac is formed during embryogenesis from an infolding of the greater omentum. The open end of the infolding, known as the omental foramen is usually close to the stomach.

Additional images[edit]

See also[edit]


  1. ^ Shahani RB, Bijlani RS, Dalvi AN, Shah HK, Samsi AB. Massive upper gastrointestinal haemorrhage due to direct visceral erosion of splenic artery aneurysm. J Postgrad Med 1994;40:220–2. Full Text.

External links[edit]

  • "Lesser sac". Medcyclopaedia. GE.[dead link]
  • Anatomy photo:37:09-0100 at the SUNY Downstate Medical Center – "Abdominal Cavity: The Lesser Peritoneal Sac"
  • Anatomy image:8070 at the SUNY Downstate Medical Center