Peritoneal Cavity and Peritoneal Attachments

The peritoneum is the serous membrane lining the abdominal cavity (parietal layer) and covering the viscera (visceral layer); the potential space between them is the peritoneal cavity. Where the membrane reflects between wall and viscera it forms the mesenteries, omenta, and ligaments that suspend organs, carry their vessels and nerves, and divide the abdomen into intraperitoneal and retroperitoneal compartments.

Definition

The peritoneum is a continuous serous membrane with parietal and visceral layers enclosing the peritoneal cavity; its reflections form the mesenteries, omenta, and ligaments that attach and suspend the abdominal viscera and define the intraperitoneal and retroperitoneal compartments.

Scope

This topic covers the parietal and visceral peritoneum, the peritoneal cavity and its greater and lesser sacs, the omental (epiploic) foramen, the mesenteries and the omenta, the peritoneal ligaments, and the recesses and paracolic gutters that channel fluid. It is a reference description of membranes, folds, and spaces, not clinical guidance.

Core questions

• How are the parietal and visceral peritoneum and the peritoneal cavity arranged?
• What distinguishes the greater sac from the lesser sac (omental bursa)?
• What is the omental foramen and what bounds it?
• How do mesenteries suspend viscera and convey their neurovascular supply?
• How do the recesses and paracolic gutters direct the flow of peritoneal fluid?

Key concepts

• Parietal and visceral peritoneum
• Greater sac and lesser sac (omental bursa)
• Omental (epiploic) foramen
• Greater and lesser omentum
• Mesentery proper, transverse and sigmoid mesocolon
• Peritoneal ligaments
• Paracolic gutters and peritoneal recesses

Mechanisms

Peritoneal mesothelium secretes a small volume of serous fluid that lubricates visceral movement during digestion and respiration. Reflections of the membrane form double layers (mesenteries) that tether mobile gut to the posterior wall while transmitting its arteries, veins, lymphatics, and nerves; recent work characterises the mesentery as one continuous structure from duodenum to rectum (coffey-oleary-2016). The lesser sac lies behind the stomach and communicates with the greater sac through the omental foramen, bounded anteriorly by the hepatoduodenal ligament. The configuration of recesses and the paracolic gutters governs how fluid, infection, and disseminated disease track within the cavity (standring-2020, moore-2018).

Clinical relevance

Peritoneal anatomy explains how fluid, infection, and tumour spread predictably along recesses and gutters, why some organs are surgically mobile and others fixed, and how the omentum participates in walling off inflammation. The entry describes structure and pathways for orientation and is not a basis for diagnosis or treatment.

Evidence & guidelines

Description follows consensus reference anatomy (standring-2020, moore-2018), updated by work reframing the mesentery as a single contiguous organ (coffey-oleary-2016). As descriptive anatomy it is not governed by clinical practice guidelines.

History

The peritoneal reflections and the omental bursa were described in classical dissection anatomy and elaborated in successive editions of standard texts (standring-2020). The traditional view of multiple separate mesenteries was revisited in 2016 with the proposal that the mesentery is a single continuous structure, prompting renewed interest in peritoneal organisation (coffey-oleary-2016).

Debates

Is the mesentery a set of separate structures or one continuous organ?

Classical anatomy described discrete mesenteries for different gut segments, but reassessment of the connective-tissue continuity from duodenum to rectum has led to the proposal that the mesentery is a single contiguous structure, a reframing that remains under discussion.

Seminal works

• standring-2020
• moore-2018
• coffey-oleary-2016

Frequently asked questions

What is the difference between intraperitoneal and retroperitoneal organs?

Intraperitoneal organs are suspended within the peritoneal cavity by a mesentery and are largely covered by visceral peritoneum, whereas retroperitoneal organs lie behind the peritoneum against the posterior body wall and are covered by peritoneum only on their anterior surface.

What is the omental (epiploic) foramen?

It is the opening that connects the greater sac of the peritoneal cavity with the lesser sac (omental bursa), bounded anteriorly by the hepatoduodenal ligament containing the portal triad.