Caput medusae is a sign of severe portal hypertension with portal-systemic shunting through the umbilical veins. The name refers to Medusa's hair once Minerva had turned it into snakes. Caput Medusae can be distinguished from inferior vena cava obstruction by determining the direction of flow in the veins below the umbilicus; it is towards the legs in caput medusae, and towards the head with inferior vena cava obstruction.