Caput medusae is the appearance of distended and engorged paraumbilical veins, which are seen radiating from the umbilicus across the abdomen to join systemic veins. The name caput medusae (Latin for "head of Medusa") originates from the apparent similarity to Medusa's hair once Athena had turned it into snakes.
The umbilical vein carries oxygenated blood from mother to fetus in utero, and normally closes within one week of birth. In portal hypertension, the umbilical vein can become re-canalized.