1 - Peritoneal Relations

Question 1

Objectives: Explain the layers and arrangement of the peritoneum

Peritoneum + Layers

Peritoneal Cavity M/F?

Answer 1

• Peritoneum: Innermost serous membrane that lines cavity, encloses viscera, two layers:
  
  • ​Parietal Peritoneum - lines abdominal wall
  • Visceral Peritoneum - encloses organs
• Peritoneal Cavity: Space b/t Parietal/Visceral
  
  • Males: Closed
  • Females: Open to outside due to Uterine Tubes​
    *

Question 2

Objectives: Identify the different parts of the peritoneal cavity

Greater Sac

Lesser Sac (Omental Bursa)

Answer 2

• Greater Sac: Main, large part of peritoneal cavity
  
  • Begins at diaphragm, continues inferiorly
  • Entered when parietal peritoneum penetrated
• Lesser Sac (Omental Bursa): Posterior to stomach
  
  • Communicates with Greater Sac through Epiploic Foramen
  • Superior Recess - Diaphragm to coronary ligament of liver
  • Inferior Recess - b/t superior part of layers of greater omentum

Question 3

Objectives: Explain the difference between intra- and retro- peritoneal organs, and identify which organs are which

Intraperitoneal vs Retroperitoneal

Primary vs Secondary Retroperitoneal

Answer 3

• Intraperitoneal: Completely encased structures; suspended from abdominal wall by mesenteries; invaginate into peritoneal cavity
  
  • Fist in a rubber glove
• Retroperitoneal: Lie outside peritoneal, only covered by peritoneum on one surface, NOT suspended; lie between abdominal wall and parietal peritoneum
  
  • Primary Retroperitoneal - Develop and remain between peritoneum and body wall
  • Secondary Retroperitoneal - Develop w/in peritoneum, but later fuse to body wall

Question 4

Objectives: Explain the difference between intra- and retro- peritoneal organs, and identify which organs are which

Intraperitoneal Organs

Primary Retroperitoneal Organs

Secondary Retroperitoneal Organs

Umbilical Folds?

Answer 4

• Intraperitoneal Organs:“Hand in glove”
  
  • Stomach, 1st / 4th Part Duodenum, Jejunum, Ileum, Cecum, Appendix, Transverse Colon, Sigmoid Colon, Spleen, Liver (except bare area), Gall Bladder
• Primary Retroperitoneal Organs:
  
  • Kidneys, Adrenal Gland, Aorta, Inferior Vena Cava, Testes, Bladder/Ureters, Uterus, Rectum
• Secondary Retroperitoneal Organs: Fuse to body wall
  
  • Duodenum (middle parts), Pancreas, Ascending Colon, Descending Colon
• Structures producing the umbilical folds are retroperitoneal

Question 5

Objectives: Identify peritoneal mesenteries, omenta, and ligaments

Mesentery

Mesenteries of the Gut: Dorsal (+parts), Ventral

Answer 5

• Mesentery:
  
  • Double layer of peritoneum that suspends viscera from body wall
  • Nerves and blood vessels travel; allow communication between organ and body wall
  • Provide mobility
• Mesenteries of the Gut
  
  • Dorsal Mesentery: Attaches viscera to Posterior Abdominal Wall; found in foregut, midgut, and most of hindgut
    
    • Greater Omentum
    • “The Mesentery”
    • Mesocolons
  • Ventral Mesentery: Attaches viscera to Anterior Abdominal Wall; develops w/liver
    
    • ​Forms covering of liver
    • Limited to terminal esophagus, stomach, proximal duodenum
    • Lesser Omentum, Falciform Ligament, Coronary Ligament, L/R Triangular Ligament

Question 6

Objectives: Identify peritoneal mesenteries, omenta, and ligaments

Recesses - Clinical relevance?

Subphrenic

Hepatorenal - Clinical relevance?

Answer 6

• Recesses (pouches): Fossae of peritoneum formed by peritoneal reflections (folds); determine the extent and direction of the spread of pathological fluids that enter the peritoneal cavity
• Subphrenic Recess: Space in greater sac between diaphragm and liver on either side of falciform ligament
• Hepatorenal Recess: Space in greater sac between liver and right kidney/diaphragm; lowest part of the abdominopelvic cavity when patient is lying down
  
  • ​Clinical: Infections could spread to lesser sac through epiploic foramen

Question 7

Objectives: Identify peritoneal mesenteries, omenta, and ligaments

Peritoneal Ligament + Omenta

Falciform Ligament

Ligamentum Teres

Answer 7

• Peritoneal Ligament - double layer of peritoneum that connects an organ with another organ/abdominal wall
• Omenta - Specific peritoneal ligaments of the stomach; pass from stomach/prox. duodenum to adj. viscera in abdominal cavity/abdominal wall
• Falciform Ligament - Connects liver to anterior abdominal wall
• Ligamentum Teres - Free edge of connection of liver to anterior abdominal wall

Question 8

Objectives: Identify peritoneal mesenteries, omenta, and ligaments

Ventral Mesentery Ligaments

Dorsal Mesentery Ligaments

Answer 8

• Ventral Mesentery Ligaments:
  
  • Lesser Omentum: Connects lesser curvature of stomach and proximal duodenum to liver
    
    • Hepatogastric Ligament
    • Hepatoduodenal Ligament; contrains portal triad
  • Falciform Ligament: Free inferior margins contain Ligamentum Teres (obliterated umbilical vein)
  • Coronary Ligament: Liver to diaphragm
  • L/R Triangular Ligaments: Liver to diaphragm
• Dorsal Mesentery Ligaments:
  
  • Greater Omentum: Hangs down from greater curvature of stomach and proximal duodenum; two double layers;
    
    • Gastrophenic, Gastrosplenic, Gastrocolic Ligaments are named
  • Splenorenal Ligament: Spleen to left kidney
  • Phreniococolic Ligament: Left Colic Flexure to Diaphragm

Question 9

Objectives: Explain how peritoneal structures allow spread of pathological fluids and infections within the abdominal cavity

Peritonitis

Spread of Infections

Peritoneal Adhesions

Answer 9

• Peritonitis: Inflammation of peritoneum; excess fluid may accumlate resulting in ascites
• Spread of Infections: Paracolic Gutters provide pathway of ascitic fluid and spread of pathological fluids; large surface area allows rapid spread; boundaries of peritoneum act as barrier; infections usually stay below diaphragm
• Peritoneal Adhesions: Fibrous bands of scar tiessue; joining organs abnormally; can cause intestinal blockages