A type of portacaval anastomoses that forms between the paraumbilical veins (of portal circulation) and the superficial epigastric vein (of systemic circulation).
They arise mainly due to portal hypertension of paraumbilical veins. These are common in patients with cruveilhier-Baumgarten syndrome.
The name is derived from their resemblance to Medusa's hair. Medusa is a Greek mythology character whose hair turned into snakes.
Also called: caput medusae