Sites of Portosystemic Anastomosis

Definition and Clinical Significance

Portosystemic anastomosis refers to the connection between the portal and systemic venous systems. These connections allow blood from the portal vein to bypass the liver in cases of increased portal pressure, such as portal hypertension. Understanding these sites is crucial in diagnosing and managing liver-related conditions.

Major Sites of Portosystemic Anastomosis

1. Esophageal Anastomosis

Located between the left gastric vein (portal system) and esophageal veins (systemic circulation). Clinically significant in esophageal varices.

2. Rectal Anastomosis

Occurs between the superior rectal vein (portal system) and middle/inferior rectal veins (systemic circulation), often leading to hemorrhoids.

3. Paraumbilical Anastomosis

Connections between the paraumbilical veins (portal system) and epigastric veins (systemic circulation), leading to caput medusae.

4. Retroperitoneal Anastomosis

Connections between portal venous tributaries and systemic veins in the posterior abdominal wall.

Clinical Relevance

The presence of portosystemic anastomoses indicates increased pressure in the portal circulation, typically seen in conditions like cirrhosis. Recognizing these sites is essential for early diagnosis and treatment.