metatarsal vein vs vena metatarsus

metatarsal vein and vena metatarsus both are nouns.

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

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

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

metatarsal vein (noun)	vena metatarsus (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