vena rectalis vs rectal vein

vena rectalis and rectal vein both are nouns.

Word	Noun	Adjective	Verb	Adverb
vena rectalis	Yes	No	No	No
rectal vein	Yes	No	No	No

As nouns, vena rectalis and rectal vein are synonyms defined as:

vena rectalis and rectal vein: any of several veins draining the walls of the anal canal and rectum

Other synonyms of vena rectalis include hemorrhoidal vein.

vena rectalis (noun)	rectal vein (noun)
any of several veins draining the walls of the anal canal and rectum	any of several veins draining the walls of the anal canal and rectum