Peritoneum

• Peritoneum


  Large thin serous membrane that lines the walls of the abdominal and pelvic cavities and covers the organs within these cavities

  
• Peritoneum


  • Made up of a tough layer of elastic tissue lined with the simple squamous epithelium
  • Largest serous sac of the body
• Parietal peritoneum


  Lines the walls of the abdominal and pelvic cavities

  
• Visceral peritoneum


  Covers the organs
• Peritoneal cavity


  • Potential space between the parietal and visceral layer of peritoneum
  • Contains no organs
  • Contains a thin layer of fluid that keeps the peritoneal surfaces moist

  
• The peritoneal cavity is a closed sac in males (cul-de-sac)

  
• In the female, there is a communication with the exterior through the uterine tubes, the uterus, and the vagina
• Epiploic foramen

  Communication between the greater sac and lesser sac/omental bursa of the peritoneal cavity

  
• Peritoneal fluid


  • Lubricates the peritoneal surfaces, enabling the viscera to move over each other without friction and allowing the movements of digestion
  • Contains leukocytes and antibodies that resist infection
  • Absorbed by lymphatic vessels on the inferior surface of the diaphragm
• Parietal peritoneum


  • Loosely attached to the walls by extraperitoneal connective tissue
  • Derived from somato-pleural layer of lateral plate mesoderm
  • Pain sensitive (as it is innervated by somatic nerves)
  • Nerve supply: same as those of overlying body wall

  
• Visceral peritoneum


  • Derived from splanchno-pleuric layer of lateral plate mesoderm
  • Cannot be stripped
  • Innervated by the autonomic nerves and therefore is insensitive to pain
  • Nerve supply: is that of underlying viscera
• Functions of peritoneum


  • Provides slippery surface for movements of viscera
  • Contains various phagocytic cells which help in protection of viscera
  • Capable of storing large amount of fat
  • Mesothelial cells can transform into fibroblasts which promote healing power
  • Acts as semi-permeable membrane; metabolites like urea can be removed from blood by peritoneal dialysis
• Intraperitoneal viscera


  Viscera are completely surrounded by peritoneum e.g. stomach and spleen
• Retroperitoneal viscera


  Covered by peritoneum partially on their anterior surfaces only e.g. kidney and ureter

  
• Mesentery


  Double layer of peritoneum that connects the small intestine to the posterior abdominal wall

  
• Mesocolon


  Double layer of peritoneum that connects the large intestine to the posterior abdominal wall

  
• Omentum


  Double-layered extension or fold that passes from the stomach and proximal part of the duodenum to adjacent organs in the abdominal cavity or to the abdominal wall

  
• Lesser omentum


  Two-layered fold of peritoneum that connects the lesser curvature of the stomach and the proximal part of duodenum to the liver

  
• Greater omentum


  Double layer of peritoneum that connects an organ with another organ or to the abdominal wall

  
• Peritoneal ligaments


  Reflections of peritoneum that connect organs to each other or to the abdominal wall

  
• Peritoneal folds


  Reflections of peritoneum that are raised from the body wall by underlying blood vessels, ducts and obliterated fetal vessels

  
• Peritoneal recesses/fossae


  Pouches of peritoneum that are formed by a peritoneal fold

  
• Anterior abdominal fossae


  • Supravesical fossa
  • Medial inguinal fossa
  • Lateral inguinal fossa

  
• Peritoneal recess or fossa


  A pouch of peritoneum that is formed by a peritoneal fold

  
• Peritoneal fossae


  • Supra-vesical fossa
  • Medial inguinal fossa
  • Lateral inguinal fossa

  
• Median umbilical fold


  • Covers median umbilical ligament - Remnant of urachus
• Medial umbilical folds


  • Covers medial umbilical ligaments - Remnants of the obliterated umbilical arteries
• Lateral umbilical folds


  • Covers the inferior epigastric vessels, which bleed if cut
• Supra-vesical fossae


  Found between the median and medial umbilical folds, formed as peritoneum reflects from the anterior abdominal wall onto the bladder, potential site for external supra-vesical hernia

  
• Medial inguinal fossae


  Found between the medial and lateral umbilical folds, potential site for the less common direct inguinal hernias
• Lateral inguinal fossae


  Found lateral to the lateral umbilical folds, potential site for most common indirect inguinal hernia
• Greater peritoneal sac


  The main and larger part of the peritoneal cavity

  
• Lesser sac or omental bursa


  Lies posterior to the stomach and adjoining structures
• Supracolic compartment


  Part of the greater sac, above the transverse mesocolon
• Infracolic compartment


  Part of the greater sac, below the transverse mesocolon
• Right infracolic space


  Triangular space, lies between root of mesentery, ascending colon, right 2/3 of transverse colon and transverse mesocolon
• Left infracolic space


  Lies between root of mesentery, descending colon, left 1/3 of transverse colon and transverse mesocolon, widens below where it is continuous with the cavity of the pelvis

  
• Right paracolic gutter


  Lies lateral to the ascending colon, communicates with the hepato-renal recess and the pelvic cavity, provides a route for the spread of infection between the pelvic and the upper abdominal region
• Left paracolic gutter


  Lies lateral to the descending colon, separated from the area around the spleen by the phrenico-colic ligament
• Omental bursa/Lesser Sac


  An extensive saclike cavity, lies posterior to stomach, and adjacent structures and the lesser omentum