vena comitans

noun

vena co·​mi·​tans -ˈkō-mə-ˌtanz 

plural venae comitantes -ˌkō-mə-ˈtan-ˌtēz 

: a vein accompanying an artery

The accompaniment is so complete, in fact, that for much of the route up the arm, the vein network forms true venae comitantes, or parallel paired veins on either side of the artery.

—Walter Carl Hartwig, Fundamental Anatomy