PERITONEUM - 1

Spleen: It is actually mesodermal in origin, not endodermal like the rest of the abdominal organs.

Retroperitoneal Space: The area behind (posterior to) the peritoneum. Any organs not completely (or almost completely) covered by peritoneum are considered retroperitoneal organs.

Abdominal Cavity: Everything but the lateral, posterior, and anterior body walls of the abdomen, including both the peritoneal cavity and the retroperitoneal space.

Peritoneal Cavity: That part of the abdomen invaginated by peritoneum.

• Peritoneum has visceral and parietal layers, just like the pleural cavity. It is analogous to the organs pushing themselves into the peritoneum, like a fist into a balloon.
  

o Visceral Peritoneum: Peritoneum directly on the organs.
o Parietal Peritoneum: Peritoneum surrounding the interior lining of the abdominal wall.

• MALES: The peritoneal cavity is CLOSED.
• FEMALES: The peritoneal cavity is OPEN. It opens out into the cervix and vagina, making it a potential space for pathogens to enter.
• Peritoneum should be considered a potential space for pathogens and fluids to build up.

Subphrenic Recess: The recess where the peritoneum reflects off the liver (right side) on the inferior surface of the diaphragm.

• It contains the coronary ligament of the liver.

• OMENTA: Peritoneum surrounding the stomach

1. Lesser Omentum: Peritoneum along the lesser curvature of the stomach, covering the pancreas. It is superior and medial to the stomach and posterior to parts of the liver, and anterior to pancreas.
   

Lesser Omental Bursa / Lesser Peritoneal Sac: The space between the stomach and the liver. The space anterior to the lesser curvature of the stomach and posterior to the liver.

• EPIPLOIC FORAMEN: A pathway that allows entrance from the lesser peritoneal sac to the greater peritoneal sac.o The Inferior Vena Cava goes directly posterior to it (retroperitoneal).

o The portal triad is directly anterior to it, in the peritoneum, along the lesser curvature of the stomach.

Greater Omental Bursa: The space between the stomach and anterior abdominal wall.

Greater Omentum: The space formed by the peritoneum on the anterior surface of the stomach and the anterior abdominal wall.
 It attaches to the stomach and to the transverse colon.
 Anterior Layer of Greater Omentum: The parietal peritoneum of the abdominal wall.
 Posterior Layer of Greater Omentum: The visceral peritoneum along the greater curvature of the stomach.

Superior Recess: Where the Lesser Omentum stops at the coronary ligament of the liver and reflects back onto the liver. Essentially, the space between the stomach and

Inferior Recess: Along the greater curvature of the stomach, where the greater omentum reflects onto the transverse mesocolon. Essentially, the space between the stomach and transverse colon, inferior to the stomach.

Intra-Peritoneal Organs: Organs completely or almost completely enclosed by peritoneum.

• Stomach
• Liver
• Gall Bladder
• Transverse Colon: completely
• Jejunum
• Ileum
• Cecum (very start of ascending colon)

Retro-Peritoneal Organs: Organs that are located mostly or completely behind the posterior parietal peritoneum.

• Duodenum
• Ascending Colon (only 25-50% covered)
• Descending Colon (only 25-50% covered)
• Sigmoid Colon
• Pancreas
• Kidneys
• Great Vessels and their primary branches: Abdominal Aorta and Inferior Vena Cava, Celiac Trunk, and Superior and Inferior Mesenteric arteries and veins.
  

Category: Anatomy Notes