vena metacarpus vs metacarpal vein

vena metacarpus and metacarpal vein both are nouns.

Word	Noun	Adjective	Verb	Adverb
vena metacarpus	Yes	No	No	No
metacarpal vein	Yes	No	No	No

As nouns, vena metacarpus and metacarpal vein are synonyms defined as:

vena metacarpus and metacarpal vein: dorsal and palmar veins of the hand

vena metacarpus (noun)	metacarpal vein (noun)
dorsal and palmar veins of the hand	dorsal and palmar veins of the hand