Topic 112. System OF Portal VEIN. Porto- Caval Anastomoses. CAVO- Caval Anastomoses PDF

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TOPIC 112. SYSTEM OF PORTAL VEIN. PORTO-CAVAL ANASTOMOSES. CAVA-CAVAL ANASTOMOSES

PORTO-CAVAL ANASTOMOSES Among the clinically most important regions of overlap between the portal and caval systems are those at each end of the abdominal part of the gastrointestinal system: -

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Around the inferior end of the esophagus. Around the inferior part of the rectum. Small veins that accompany the degenerate umbilical vein (round ligament of the liver) establish another important portacaval anastomosis. o The round ligament of the liver connects the umbilicus of the anterior abdominal wall with the left branch of the portal vein as it enters the liver. The small veins that accompany this ligament form a connection between the portal system and paraumbilical regions of the abdominal wall, which drain into systemic veins. Other regions where portal and caval systems interconnect include: o where the liver is in direct contact with the diaphragm (the bare area of the liver); o where the wall of the gastrointestinal tract is in direct contact with the posterior abdominal wall (retroperitoneal areas of the large and small intestine); and o the posterior surface of the pancreas (much of the pancreas is secondarily retroperitoneal).

When the pressure in the portal vein is elevated, venous enlargement (varices) tend to occur at and around the sites of portosystemic anastomoses and these enlarged veins are called: -

varices at the anorectal junction esophageal varices at the gastroesophageal junction caput medusae at the umbilicus.

Esophageal varices are susceptible to trauma and, once damaged, may bleed profusely, requiring urgent surgical intervention.

CAVOCAVAL ANASTOMOSES...