any vein of the four pairs collecting blood from the muscles and integument of the loins, the walls of the abdomen, and adjacent parts and emptying into the dorsal part of the inferior vena cava
lumbar vein
noun(lumbar vein)
a longitudinal vein on each side that connects the lumbar veins and is frequently the origin of the azygos vein on the right side and of the hemiazygos vein on the left