Vitelline veins

The vitelline veins are veins which drain blood from the yolk sac.

They run upward at first in front, and subsequently on either side of the intestinal canal.

They unite on the ventral aspect of the canal, and beyond this are connected to one another by two anastomotic branches, one on the dorsal, and the other on the ventral aspect of the duodenal portion of the intestine, which is thus encircled by two venous rings; into the middle or dorsal anastomosis the superior mesenteric vein opens.