common cardinal vein

n.
  1. Any of the major drainage channels that are formed by anastomosis of the anterior and posterior cardinal veins and are the main systemic return channels to the heart in the embryos of humans and other vertebrates.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.