Lecture on Peritoneum by Dr. Alsup

Introduction

• Discussing the peritoneum
• Goal: Understanding definitions and basic concepts of mesenteries and omenta
• Detailed discussions on specific regions related to organs will follow in later lectures

What is Peritoneum?

• Peritoneum: A serous membrane lining the abdominopelvic cavity
  • Largest serous membrane in the body
  • Includes both the abdominal and pelvic cavities
• Similar to the pleura in the thoracic cavity
  • Parietal Peritoneum: Attached to abdominal wall
    • Connected by extraperitoneal connective tissue
  • Visceral Peritoneum: Adhered to surfaces of abdominal viscera
    • Suspends viscera within the abdominal cavity

Peritoneal Cavity

• Space between parietal and visceral peritoneum
• Often depicted larger in images than it is
• Contains peritoneal fluid for lubrication and defense
• Greater Sac: Majority of the peritoneal cavity
• Lesser Sac (omental bursa): Located posterior to the stomach and lesser omentum, anterior to the pancreas
• Communication: Greater and lesser sacs connect via the epiploic (omental) foramen of Winslow

Mesenteries

• Double layer of peritoneum attaching intraperitoneal viscera to the posterior abdominal wall
  • Allows neurovasculature supply or drainage
  • Serves as an anchoring point
• Named based on location, often with the prefix "meso" (e.g., transverse mesocolon, mesoappendix)
• THE Mesentery: Refers specifically to the mesentery of the jejunum and ileum (large and dominant)

Omenta

• Made of the same material as mesenteries but specifically associated with the stomach and proximal duodenum
• Lesser Omentum: Extends from lesser curvature of the stomach to the proximal duodenum
  • Subdivided into ligaments: hepatogastric, hepatoduodenal
• Greater Omentum: Extends from the greater curvature of the stomach to the proximal duodenum
  • Includes the gastrocolic ligament (omental apron)
  • The omental apron hangs over small intestines and attaches to the transverse colon (four layers in total)

Peritoneal Ligaments

• Double layers of peritoneum connecting viscera to other organs or to the abdominal wall
• Examples: hepatogastric (liver to stomach), hepatoduodenal (liver to duodenum)

Peritoneal Folds

• Peritoneum covers a structure, causing a bump
• Prominent examples: median, medial, and lateral umbilical folds

Summary

• Understanding terms related to peritoneum is essential for gastrointestinal anatomy
• Terms mostly describe specific areas of peritoneum and their connections
• Essential to be comfortable with these terms for further study
• Feel free to ask questions for clarification

Closing

• Encouragement to review and reach out with any questions
• Have a great rest of the day!