Anatomy of the Peritoneum

Introduction

• The peritoneum is a serous membrane that lines the abdominal wall and surrounds various organs in the abdominal cavity.
• The lecture covers:
  • Parts of the peritoneum
  • Lesser and greater omentum
  • Mesentery
  • Structures found in the peritoneal cavity

Functions of the Peritoneum

• Protects and fixates abdominal organs in place.
• Provides a smooth, wet environment for organs within the abdominal cavity.

Structure of the Peritoneum

1. Parietal Peritoneum

   • Lines the internal surface of the abdominal and pelvic walls.
   • 3D structure: Starts at the anterior abdominal wall, wraps to the lateral and posterior walls.

2. Visceral Peritoneum

   • Lines the walls of the organs, creating a serous coat.
   • Contains fluid produced by the peritoneum.

3. Peritoneal Cavity

   • The space between the parietal and visceral peritoneum filled with serous fluid.

Coverage of Organs by the Visceral Peritoneum

• Intraperitoneal Viscera

  • Completely invested in the visceral peritoneum (e.g., stomach, spleen, caecum, appendix, transverse colon, sigmoid colon, jejunum, ileum).

• Mesoperitoneal Organs

  • Covered by visceral peritoneum on three sides (e.g., liver, gallbladder, ascending/descending colon, middle rectum, urinary bladder when full).

• Retroperitoneal Organs

  • Covered by visceral peritoneum on one side (e.g., duodenum, pancreas, kidneys, ureters, urinary bladder when empty).

Course of the Peritoneum

• The parietal peritoneum continues as the visceral peritoneum through ligaments:
  1. Falciform Ligament
  2. Coronary Ligament
  3. Right and Left Triangular Ligaments

Greater and Lesser Omentum

• Lesser Omentum:

  • Ligaments connecting the liver to the stomach and duodenum (Hepatogastric and Hepatoduodenal ligaments).

• Greater Omentum:

  • Composed of three ligaments (Gastrophrenic, Gastrosplenic, Gastrocolic) extending from the greater curvature of the stomach.
  • Acts as a protective layer and has 4 layers due to its double-layered structure.

Mesentery

• Connects the intestines to the posterior abdominal wall.
• Composed of:
  1. Transverse Mesocolon
  2. Mesentery related to the small intestines and sigmoid colon.
• The root of the mesentery starts at the 2nd lumbar vertebra.

Peritoneal Cavity Levels

1. Upper Level

   • Contains recesses and bursae:
     • Subphrenic Recess
     • Subhepatic Recess
     • Omental Bursa (lesser sac)

2. Middle Level

   • Includes recesses around various organs:
     • Superior/Inferior Duodenal Recess
     • Superior/Inferior Ileocecal Recess
     • Rectocaecal Recess
     • Intersigmoid Recess

3. Lower Level

   • Recesses in females (Rectouterine & Vesicouterine Pouches) and males (Rectovesical Pouch).

Conclusion

• The lecture provides a detailed overview of the anatomy and functions of the peritoneum, its parts, the relationships between the visceral and parietal peritoneum, and structures found within the peritoneal cavity.