بسم الله الرحمن الرحيم Peritoneum

Objectives Define Peritoneum. Enumerate its functions. Explain the general organization of the peritoneum. Distinguish between Intraperitoneal and Retroperitoneal Structures. Describe Peritoneal Ligaments. Define lesser and greater omenta. Understand the location of epiploic foramen. Discuss mesentery and mesocolon. Explain the Peritoneal sacs.

Peritoneum Is a double-layer serous membrane. 1.Parietal layer: lines abdomino pelvic wall & folds back on itself forming a double Membrane: mesentery Functions of mesentery:- (1)Provides support: Intestines: Mesentery & Mesocolon. Stomach: Omenta. Liver: Falciform ligament. (2) Prevents intestinal twisting (3) Stores fat (4) Pathway for vessels & nerves 2. Visceral Layer: covers the organs. Peritoneal cavity: Potential space containing a bit of serous fluid.

The Peritoneum The parietal peritoneum The visceral peritoneum The peritoneal cavity

The visceral peritoneum The peritoneal cavity

Peritoneum in sagittal section

Peritoneum in transverse section

Peritoneal versus Retroperitoneal (transverse section) Most of the internal organs are surrounded by visceral peritoneum: INTRAPERITONEAL Structures. Some organs (e.g. kidneys) are between peritoneum on one surface, and the body wall on the other: RETROPERITONEAL Structures.

Peritoneal versus Retroperitoneal (sagittal section)

The retroperitoneal Structures kidneys suprarenal glands ureters duodenum pancreas aorta inferior vena cava nerves ascending colon descending colon

Peritoneal ligaments, Omenta & Mesenteries Two layers fold of peritoneum that connect solid viscera to the abdominal walls, e.g. Falciform ligament, Triangular ligaments & Coronary ligaments of the liver. Omenta: Two layers fold of peritoneum that connect the stomach to another viscus, e.g. greater & lesser omenta. Mesenteries: Two layers fold of peritoneum connecting parts of the intestine to the posterior abdominal wall, e.g. mesentery of small intestine, transverse mesocolon, sigmoid mesocolon.

Peritoneal folds related to the stomach The greater omentum: Lies between the Stomach and the anterior abdominal wall.

Peritoneal folds related to the stomach The lesser omentum Passes from the lesser curvature of the stomach and first part of the duodenum to the inferior surface of the liver.

Greater omentum

Peritoneal folds related to the stomach and Kidney The gastrosplenic (gastrolienal) ligament: Passes from the greater curvature of the stomach to the spleen. Splenorenal (lienorenal) ligament: Connects the spleen to the posterior abdominal wall over the left kidney.

Peritoneal folds related to the Stomach The gastrophrenic ligament : Connects the superior part of the greater curvature of the stomach to the diaphragm.

Peritoneal folds related to the Liver The Falciform ligament: Passes from the parietal peritoneum on the anterior abdominal wall to the visceral peritoneum on the surface of the liver. The round ligament of the liver (ligamentum teres hepatis): Is the obliterated umbilical vein and it is found in the inferior free margin of the Falciform ligament.

Peritoneal folds related to the Liver Coronary ligament: Attaches the liver to the diaphragm. Two peritoneal ligaments are parts of the coronary ligament: 1. Left triangular ligament: Is between the left lobe of the liver and the diaphragm. 2. Right triangular ligament: Is between the right lobe of

Mesentery of the small intestine The mesentery suspends the jejunum and ileum from the posterior abdominal wall.

Mesoappendix: Attaches the appendix to the posterior abdominal wall and it contains the appendicular artery.

Peritoneal folds & ligaments of colon Transverse mesocolon: Attaches the transverse colon to the posterior abdominal wall. Phrenicocolic ligament: Attaches the left colic flexure to the diaphragm. Sigmoid mesocolon: Suspends the sigmoid colon from the posterior abdominal wall.

Peritoneal sacs Peritoneal structures all are found within a subdivision of the peritoneal cavity called the greater peritoneal sac. Posterior to the stomach and lesser omentum is a smaller subdivision of the peritoneal cavity called the lesser peritoneal sac (omental bursa). The omental foramen (epiploic foramen, foramen of Winslow) connects the greater and lesser peritoneal sacs.

The Omental foramen Boundaries: • Anterior: Hepatic portal vein, hepatic artery and bile duct contained within the lesser omentum. • Posterior: Inferior vena cava & right crus of the diaphragm covered with parietal peritoneum. • Superior: Caudate lobe of the liver covered with visceral peritoneum. Inferior: First part of the duodenum covered with visceral peritoneum.

2. Lesser and Greater Omenta

Lesser and Greater Omenta hepatogastric ligament Lesser Omentum hepatoduodenal ligament the epiploic foramen (of Winslow)

Greater Omentum

3. The mesenteries

The mesenteries Contents ? mesentery of the small intestine transverse mesocolon sigmoid mesocolon

Lesser Sac

The supra-colic compartment

Lt. anterior subphrenic space Rt. anterior subphrenic space Lt. anterior subphrenic space Rt. posterior subphrenic (Rt. Subhepatic)

left subhepatic Space (Lt. posterior subphrenic) Morison’s pouch

Nerve supply to the peritoneum The parietal peritoneum phrenic nerve intercostal first lumbar nerves obturator nerve The visceral peritoneum autonomic

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