Abdomen: Peritoneal Cavity

Abdomen > Peritoneal Cavity > Study Aims
STUDY AIMS
At the end of your study, you should be able to:
Understand the difference between the abdominopelvic and peritoneal cavities
Be able to explain the difference between the greater sac and the lesser sac (omental bursa)
Understand the organization of the peritoneal folds that form the greater omentum, lesser omentum, the mesentry of the small intestine, and other mesenteries and peritoneal ligaments
Know which organs are intraperitoneal, retroperitoneal, and secondarily retroperitoneal
Describe the subdivisions of the peritoneal cavity

Abdomen > Peritoneal Cavity > Guides
GUIDE

4-3: Abdomen: Peritoneal Cavity
    Peritoneum (Plate 274 and Plate 348)
  • Serous membrane
    • Lines the abdominopelvic cavity (Fig. 4-3-1)
    • Consists of two continuous layers of mesothelium:
    • Parietal peritoneum
      • Lines the internal abdominal wall
      • Receives its neurovascular supply from the region of the wall it lines
    • Visceral peritoneum
      • Invests abdominal viscera
      • Receives its neurovascular supply from that of organ
  • Peritoneal cavity
    • A potential space between the parietal and visceral layers of the peritoneum
    • Contains a thin film of fluid
    • No organs actually lie within in this potential space
    • Males: peritoneal cavity is completely closed
    • Females: communicates with exterior of body via uterine tubes, uterus, and vagina
  • Intraperitoneal organs
    • Are organs nearly totally covered by visceral peritoneum
    • Not actually inside the peritoneal cavity, but project into the peritoneal cavity
    • Are covered by peritoneum
    • Are attached to body wall and other organs by mesenteries and ligaments
    • Include:
      • Liver
      • Spleen
      • Stomach
      • First part of duodenum
      • Jejunum
      • Ileum
      • Transverse colon
      • Sigmoid colon
      • Superior rectum
  • Primarily retroperitoneal organs
    • Organ that develop and remain beneath the parietal peritoneum
    • Only the kidneys
  • Secondarily retroperitoneal organs
    • Organs that developed with a short mesentery
    • Become pushed against parietal peritoneum lining the body wall by growth of other organs, primarily the small intestine.
    • Mesentery of organ fuses with parietal peritoneum: fusion fascia
    • Peritoneum covers only its anterior surface, hence, secondarily retroperitoneal
    • Organ can be freed at its lateral edge, along the plane of the fusion fascia
    • Include
      • Adrenal glands
      • Pancreas
      • Parts two through four of the duodenum
      • Ascending and descending colon
    Omenta (Plate 269 and Plate 272)
  • Omentum = double-layered fold of peritoneum
  • Lesser omentum: connects lesser curve of stomach and proximal duodenum to liver
    • Passes from the stomach and first part of the duodenum to adjacent organs
    • Consists of two parts:
      • Hepatogastric ligament
      • Hepatoduodenal ligament
  • Greater omentum
    • Hangs down from the greater curve of the stomach and proximal duodenum
    • Folds back on itself to attach to the transverse colon
    Mesenteries (Plate 271)
  • Mesentery = double layer of peritoneum created by invagination of peritoneum by an organ
  • Is the continuity of visceral and parietal peritoneum
  • Provides a pathway for neurovascular communication between organ and body wall
  • Contains lymph nodes and variable amounts of fat
  • The mesentery is the mesentery of the small intestine
  • The mesocolon is the mesentery of the large intestine
    • Transverse mesocolon
    • Sigmoid mesocolon
    Peritoneal ligaments
  • Ligament = double layer of peritoneum connecting an organ to another organ or to the abdominal wall
  • Ligaments of the liver:
    • Falciform ligament: from liver to anterior abdominal wall
    • Gastrohepatic ligament
      • From lesser curvature of stomach to liver
      • = a portion of lesser omentum
    • Hepatoduodenal ligament
      • From the liver to the first part of the duodenum
      • = Right, thickened free edge of lesser omentum
      • Contains portal triad (portal vein, hepatic artery, bile duct)
  • Ligaments of the stomach
    • Gastrophrenic ligament: from stomach to inferior diaphragmatic surface
    • Gastrosplenic ligament: from stomach to hilum of spleen
    • Gastrocolic ligament: from stomach as the greater omentum to the transverse colon
  • Ligaments of the spleen
    • Gastrosplenic: from stomach to hilum of spleen
    • Splenorenal (lienorenal): from spleen to the left kidney
  • Phrenicocolic ligament (sustentaculum lienis)
    • From the left hepatic flexure of transverse colon to diaphragm
    • Supports the spleen
    Peritoneal subdivisions (Plate 272)
  • Greater sac: main peritoneal cavity
  • Lesser sac (omental bursa) (Plate 273)
    • Posterior to the stomach
    • Visible through the lesser omentum
    • Superior recess: limited by the diaphragm and posterior layers of the coronary ligament of the liver (Section 4-4: AbdomenViscera (Gut))
    • Inferior recess: potential space between layers of the greater omentum
    • Communicates with the greater sac via the epiploic foramen (of Winslow) (Table 4-3-1 for boundaries)
  • Supracolic compartment
    • Greater sac above the transverse mesocolon
    • Contains stomach, liver, and spleen
  • Infracolic compartment
    • Greater sac below transverse mesocolon,
    • Contains small bowel, ascending and descending colon.
    • Divided into left and right divisions by the mesentery of the small intestine
    • Free communication between the supracolic and infracolic compartments via the paracolic gutters
      • Grooves or recesses between the ascending and descending colon and the posterior abdominal wall along their lateral borders
Abdomen > Peritoneal Cavity > Figures
FIGURES
Plate 273: Abdomen: Peritoneal Cavity—Omental Bursa: Cross Section
Fig. 4-3-1: Longitudinal section through the abdomen to show its shape and superior and inferior boundaries. (From Gosling JA, Harris PF, Whitmore I, et al. Human Anatomy, 4th edition. Mosby, 2005, p. 125, Fig. 4.4)
Abdomen > Peritoneal Cavity > Tables
TABLES

Table 4-3-1:Boundaries of the epiploic foramen
Boundary Structures
Anterior Hepatoduodenal ligament containing portal triad
Posterior Inferior vena cava (IVC) and right crus of diaphragm (covered by parietal peritoneum)
Superior Caudate lobe of liver (covered by visceral peritoneum)
Inferior First part of duodenum, portal vein, hepatic artery, bile duct
(Courtesy of Sam Yasen, MBBS, BSc)

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