The Greater and lesser sacs

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Which structure divides the greater sac into two, and what are the resulting compartments called?

Answer: The transverse colon divides the greater sac into the supracolic compartment (superior to the transverse colon) and the infracolic compartment (inferior to the transverse colon).

What foramen marks the opening between the greater and lesser sacs?

Answer: The epiploic foramen of Winslow.

What are the boundaries of the foramen of Winslow?

Anterior: The hepatoduodenal ligament and the free edge of the lesser omentum.
Posterior: Peritoneum/Inferior Vena Cava.
Superior: Caudate lobe of the liver.
Inferior: 1st part of the duodenum and the hepatic artery.

Describe the mechanism and indication for Pringle’s manoeuvre.

Answer: The Pringle’s manoeuvre involves compression of the hepatic artery, common bile duct, and portal vein as they run in the free edge of the foramen of Winslow. This manoeuvre is used to control bleeding from the liver.
Placing a finger into the foramen of Winslow and compressing the hepatic triad should not be carried out for more than 120 minutes due to the risk of reperfusion injury to the liver.

What are the boundaries of the lesser sac?

Anterior: Lesser omentum, visceral peritoneum along posterior stomach, and gastrocolic omentum.
Left lateral: Spleen, attached by the gastrosplenic and splenorenal ligaments.
Right: Foramen of Winslow.
Posterior: Visceral/parietal peritoneum covering the diaphragm, left kidney/adrenal gland, and duodenum.
Superior: Peritoneum covering the caudate lobe of the liver.

Describe the embryological development of the lesser sac.

Answer: The rotation of the stomach by 90 degrees causes the spleen to move left and the liver to move right, accommodating the growing abdominal organs. This twisting of the peritoneum results in the formation of the falciform ligament, lesser omentum, and coronary ligaments of the liver, creating the cavity of the lesser sac.

If a loop of intestine becomes strangulated in the lesser sac via the foramen of Winslow, how should this be managed?

Answer: Needle decompression should be performed, as none of the foramen's boundaries can be incised.

The boundaries of the epiploic foramen of Winslow cannot be incised because they are formed by critical structures that are not easily accessible or suitable for surgical incision without causing significant harm.

Anterior: The hepatoduodenal ligament and the free edge of the lesser omentum, which contain important structures like the common bile duct, hepatic artery, and portal vein. Incising these structures would compromise vital blood flow and biliary function.

Posterior: The peritoneum and the inferior vena cava (IVC). The IVC is a major vein responsible for returning deoxygenated blood from the lower body to the heart. Any damage to the IVC could result in severe bleeding and circulatory issues.

Superior: The caudate lobe of the liver. Incising the liver could lead to massive bleeding and liver damage.

Inferior: The first part of the duodenum and the hepatic artery. The duodenum is a critical part of the digestive system, and the hepatic artery supplies blood to the liver, gallbladder, and parts of the stomach. Damaging either could lead to serious complications.