ascending lumbar vein

n.
  1. A vein that arises from the sacral and lumbar veins and at the diaphragm becomes the azygos vein on the right side and the hemiazygos vein on the left.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.