What are the key structures and landmarks of the abdominal cavity, including the parietal (peritoneum lining the abdominal wall) and visceral (peritoneum covering organs) peritoneum, greater omentum, lesser omentum, peritoneal cavity, gastrointestinal (GI) tract, posterior abdominal wall, gastrohepatic ligament, hepatoduodenal ligament, omental bursa (lesser sac), and omental foramen (epiploic foramen, foramen of Winslow)?

Key Abdominal Cavity Structures and Landmarks for Cadaver Identification

The abdominal cavity is a complex anatomical space with distinct peritoneal structures that can be identified through specific landmarks during cadaver dissection.

Peritoneum

Parietal Peritoneum

• Lines the abdominal wall and undersurface of the diaphragm
• Appears as a thin, shiny membrane adhering to the inner surface of the abdominal wall
• Landmark: Can be identified by gently separating it from the transversalis fascia; appears continuous with the visceral peritoneum at points where it reflects onto organs

Visceral Peritoneum

• Covers the intraperitoneal organs
• Appears as a thin, glistening membrane closely adherent to organ surfaces
• Landmark: Follows the contours of organs; can be distinguished from parietal peritoneum by its intimate attachment to organ surfaces

Greater Omentum

• Large, fatty, apron-like structure hanging from the greater curvature of the stomach
• Contains vascular-fatty arcades and lymphoid nodules (milky spots)
• Landmark: Easily identified as the first structure encountered upon opening the anterior abdominal wall; typically covers the small intestines

Lesser Omentum

• Consists of two parts: hepatogastric ligament and hepatoduodenal ligament
• Landmark: Located beneath the liver; becomes visible only after lifting the liver upward
• Contains vascular-fatty spurs between serous-reticular membranes

Peritoneal Cavity

• Potential space between parietal and visceral layers of peritoneum
• Divided into supramesocolic and inframesocolic compartments
• Landmark: Can be visualized when containing fluid; otherwise appears as a virtual space

Gastrointestinal Tract

• Includes stomach, small intestine, and large intestine
• Landmark: Stomach identified by its J-shape and location under the left diaphragm; small intestine by its mesentery attachment; large intestine by its haustra and taeniae coli

Posterior Abdominal Wall

• Formed by lumbar vertebrae, psoas muscles, quadratus lumborum, and iliacus muscles
• Landmark: Exposed after removal of abdominal organs; psoas muscles form distinct longitudinal ridges on either side of the vertebral column

Gastrohepatic Ligament

• Part of the lesser omentum extending from liver to lesser curvature of stomach
• Landmark: Thin membrane visible when lifting the liver; connects liver's visceral surface to lesser curvature of stomach

Hepatoduodenal Ligament

• Part of the lesser omentum containing portal triad (portal vein, hepatic artery, bile duct)
• Landmark: Thicker portion of lesser omentum; can be identified by performing the Pringle maneuver (pinching between thumb and index finger)

Omental Bursa (Lesser Sac)

• Peritoneal pouch behind the stomach
• Landmark: Accessed through the omental foramen; bounded by stomach anteriorly and pancreas posteriorly

Omental Foramen (Epiploic Foramen, Foramen of Winslow)

• Opening connecting the greater and lesser peritoneal sacs
• Landmark: Located behind the free edge of the hepatoduodenal ligament; bounded by:
  • Anteriorly: hepatoduodenal ligament with portal vein
  • Posteriorly: inferior vena cava
  • Superiorly: caudate lobe of liver
  • Inferiorly: first part of duodenum

Important Relationships and Clinical Considerations

• The peritoneal cavity is subdivided by mesenteries and ligaments that direct the flow of intraperitoneal fluid 1
• The right paracolic gutter communicates freely with both the pelvis and right subphrenic space, while the left paracolic gutter is separated from the left subphrenic space by the phrenicocolic ligament 2
• Understanding the relationship between the anterior peritoneal reflection and rectal tumors is crucial for predicting local and peritoneal recurrence risk 3
• The vestibule of the omental bursa is bounded by the gastropancreatic fold, which forms an important boundary of the epiploic foramen 4

Tips for Cadaver Identification

1. Begin with identifying the greater omentum as the most superficial structure
2. Lift the liver to identify the lesser omentum and its components
3. Trace the peritoneal reflections to understand the compartmentalization
4. Use the portal triad within the hepatoduodenal ligament as a key landmark
5. Identify the omental foramen by placing a finger behind the free edge of the hepatoduodenal ligament

Understanding these structures and their relationships is essential for surgical approaches, interpretation of radiological images, and assessment of intra-abdominal pathology 5.