vena metatarsus vs metatarsal vein

vena metatarsus and metatarsal vein both are nouns.

Word	Noun	Adjective	Verb	Adverb
vena metatarsus	Yes	No	No	No
metatarsal vein	Yes	No	No	No

As nouns, vena metatarsus and metatarsal vein are synonyms defined as:

vena metatarsus and metatarsal vein: dorsal and plantar branches of veins serving the metatarsal region of the foot

vena metatarsus (noun)	metatarsal vein (noun)
dorsal and plantar branches of veins serving the metatarsal region of the foot	dorsal and plantar branches of veins serving the metatarsal region of the foot