Boundaries and Recesses of the Lesser and Greater Sac

Introduction

The peritoneal cavity consists of several compartments, including the greater sac and the lesser sac (also known as the omental bursa). These sacs are crucial in understanding intra-abdominal structures and surgical approaches.

Boundaries of the Lesser Sac (Omental Bursa)

The lesser sac is located posterior to the stomach and communicates with the greater sac via the epiploic foramen (Foramen of Winslow). It is bounded by various anatomical structures:

Anterior Boundary: The stomach, the lesser omentum (hepatogastric and hepatoduodenal ligaments).
Posterior Boundary: The peritoneum covering the pancreas, left kidney, adrenal gland, and diaphragm.
Superior Boundary: The peritoneum of the caudate lobe of the liver.
Inferior Boundary: The transverse mesocolon.
Lateral Boundaries: The splenorenal and gastrosplenic ligaments on the left.

Recesses of the Lesser Sac

The lesser sac is divided into recesses that allow movement of surrounding organs:

Superior Recess: Lies between the diaphragm and the liver.
Inferior Recess: Extends downward behind the stomach.
Splenic Recess: Positioned near the spleen and its associated ligaments.

Greater Sac and Its Compartments

The greater sac is the larger peritoneal compartment and is divided by the transverse mesocolon into two main regions:

Supramesocolic Compartment: Contains the stomach, liver, spleen, and pancreas.
Inframesocolic Compartment: Houses the small intestine and large intestine.

Clinical Relevance

The anatomical positioning of the lesser and greater sacs is crucial in surgical procedures, including pancreatic surgeries and peritoneal fluid drainage. Pathologies such as gastric perforation can lead to peritonitis affecting the lesser sac.

Conclusion

Understanding the boundaries and recesses of the lesser and greater sacs provides fundamental knowledge for both anatomy and clinical applications. This knowledge aids in surgical planning and diagnoses related to peritoneal cavities.