Vessel
Portosystemic anastomoses
Communications between portal tributaries and systemic veins
High-yield
Key regions are lower esophagus, anorectum, umbilical wall and retroperitoneum. Each pairs a portal tributary with a vein returning toward the venae cavae.
Overview
Portal and systemic venous channels meet at several anatomical sites. When portal pressure rises, these pathways can carry increased bypass flow and enlarge into clinically important collateral veins.
Reference facts
- Origin
- Portal partners include left gastric, superior rectal, paraumbilical and colonic veins.
- Course
- Cross-system connections occur in distal esophageal, anorectal, umbilical and retroperitoneal tissues.
- Branches
- Systemic partners include azygos tributaries, middle/inferior rectal veins, abdominal-wall veins and retroperitoneal venous networks.
- Supplies
- These are venous collateral pathways, not arteries supplying an organ.
- Drains to
- Can divert portal blood toward superior or inferior caval drainage without first traversing hepatic sinusoids.
Mnemonic
Map the connections by region: esophagus, rectum, umbilicus, posterior abdominal wall.
Clinical correlation
Gastroesophageal varices can bleed severely. Anorectal varices belong to the same pressure-related collateral process but are distinct from ordinary hemorrhoids, which involve anal vascular cushions.
Frequently asked questions
Where do the portosystemic anastomoses originate?
The portosystemic anastomoses arise from the portal partners include left gastric, superior rectal, paraumbilical and colonic veins.
What do the portosystemic anastomoses supply?
The portosystemic anastomoses supply the these are venous collateral pathways, not arteries supplying an organ.
Where do the portosystemic anastomoses drain to?
The portosystemic anastomoses drain to the can divert portal blood toward superior or inferior caval drainage without first traversing hepatic sinusoids.
What are the branches of the portosystemic anastomoses?
Systemic partners include azygos tributaries, middle/inferior rectal veins, abdominal-wall veins and retroperitoneal venous networks.