caput medusae

In portal hypertension (commonly due to cirrhosis), elevated pressure in the portal venous system leads to the opening of portosystemic anastomoses to decompress the portal circulation. One key collateral pathway involves the paraumbilical veins, which connect the left portal vein to the systemic venous system via the epigastric veins of the abdominal wall. This results in visibly distended, tortuous veins radiating from the umbilicus—caput medusae. Blood flow in these veins is typically directed away from the umbilicus (unlike the flow pattern seen in inferior vena cava obstruction, where flow is directed toward the umbilicus, a distinguishing clinical test). Caput medusae is one of several classic signs of portal hypertension, alongside esophageal varices, hemorrhoids, splenomegaly, and ascites. Clinically, it is often associated with other stigmata of chronic liver disease such as spider angiomata, palmar erythema, gynecomastia, and jaundice. The finding underscores significant portosystemic shunting and warrants evaluation for underlying cirrhosis or other causes of portal hypertension (e.g., portal vein thrombosis, Budd-Chiari syndrome).