Peritoneal Cavity Spaces

The peritoneal cavity is a potential space between the parietal and visceral layers of the peritoneum. Although this cavity normally contains only a small amount of lubricating serous fluid, it is subdivided into anatomical compartments and spaces by reflections of the peritoneum. These subdivisions are crucial for the movement of peritoneal fluid, the spread of infections, abscesses, blood, or tumors, and for surgical access and imaging interpretation. Understanding the peritoneal cavity spaces is essential for clinicians dealing with abdominal trauma, disease localization, and operative procedures.

Overview of the Peritoneal Cavity

The peritoneal cavity is completely enclosed in males but communicates with the exterior in females via the uterine tubes, uterus, and vagina. It is divided into the greater sac and the lesser sac (omental bursa), with several dependent spaces or recesses formed by folds of peritoneum.

• Greater sac: The main compartment of the peritoneal cavity, extending from the diaphragm to the pelvic cavity
• Lesser sac (omental bursa): A smaller compartment behind the stomach and lesser omentum
• Epiploic (omental) foramen: Connects the greater and lesser sacs

Major Peritoneal Spaces and Compartments

1. Supracolic and Infracolic Compartments

The greater sac is divided by the transverse colon and its mesocolon into two main compartments:

• Supracolic compartment: Located above the transverse colon; contains the liver, stomach, and spleen
• Infracolic compartment: Located below the transverse colon; contains the small intestine and ascending/descending colon

2. Right and Left Infracolic Spaces

These are subdivisions of the infracolic compartment formed by the attachment of the mesentery of the small intestine:

• Right infracolic space: Between the mesentery and ascending colon
• Left infracolic space: Between the mesentery and descending colon

3. Paracolic Gutters

Paracolic gutters are longitudinal peritoneal recesses that lie lateral to the ascending and descending colon. They allow for the movement of peritoneal fluid and potentially infectious materials.

Paracolic Gutter	Location	Clinical Note
Right paracolic gutter	Lateral to ascending colon	Communicates freely with hepatorenal recess and pelvis
Left paracolic gutter	Lateral to descending colon	Less deep; limited superiorly by phrenicocolic ligament

Lesser Sac (Omental Bursa)

The lesser sac lies posterior to the stomach and lesser omentum and allows for free movement of the stomach during digestion.

Boundaries of the Lesser Sac

• Anterior: Stomach, lesser omentum
• Posterior: Pancreas, left kidney, adrenal gland
• Superior: Caudate lobe of liver
• Inferior: Greater omentum
• Left: Spleen and gastrosplenic ligament
• Right: Epiploic foramen (connects to greater sac)

It is the site of posterior gastric ulcer perforations and pancreatic fluid collections.

Pelvic Peritoneal Spaces

In the pelvis, peritoneal reflections between organs create recesses that vary between sexes and are clinically important for fluid accumulation.

In Males

• Rectovesical pouch: Between rectum and bladder; the most dependent part of the peritoneal cavity in males

In Females

• Vesicouterine pouch: Between bladder and uterus
• Rectouterine pouch (Pouch of Douglas): Between uterus and rectum; the most dependent part of the peritoneal cavity in females

Hepatorenal Recess (Morison’s Pouch)

This is a deep recess located between the right lobe of the liver and the right kidney. It is the most dependent space in the supine position and a common site of fluid accumulation from:

• Ascites
• Hemoperitoneum (trauma)
• Infection (e.g., perforated ulcer, appendicitis)

Boundaries

• Anterior: Liver
• Posterior: Right kidney and adrenal gland
• Inferior: Duodenum and colon

Clinical Importance of Peritoneal Spaces

Ascites

• Excess peritoneal fluid often accumulates in dependent spaces such as pelvis and hepatorenal recess
• Common in cirrhosis, malignancy, and heart failure

Peritonitis and Fluid Spread

• Infection or inflammation can spread via gravity and fluid movement through peritoneal spaces
• Right paracolic gutter may transmit infection from pelvis to subphrenic space

Abscess Formation

• Localized abscesses may form in:
  • Subphrenic spaces
  • Pelvic pouches
  • Lesser sac (e.g., post-pancreatitis)

Peritoneal Dialysis

• Access to peritoneal cavity spaces, particularly pelvis, is used therapeutically in renal failure

Summary of Key Peritoneal Spaces

Space	Location	Key Notes
Supracolic	Above transverse colon	Liver, stomach, spleen
Infracolic (R & L)	Below transverse colon	Small intestine and colon
Paracolic gutters	Lateral to ascending/descending colon	Fluid spread pathways
Lesser sac	Behind stomach	Posterior ulcer and pancreas site
Hepatorenal recess	Between liver and kidney	Fluid collects here when supine
Rectouterine pouch	Female pelvis	Lowest point in upright position
Rectovesical pouch	Male pelvis	Lowest point in males