sinus coronarius vs coronary sinus

sinus coronarius and coronary sinus both are nouns.

Word	Noun	Adjective	Verb	Adverb
sinus coronarius	Yes	No	No	No
coronary sinus	Yes	No	No	No

As nouns, sinus coronarius and coronary sinus are synonyms defined as:

sinus coronarius and coronary sinus: a short sinus receiving most of the veins of the heart; empties into the right atrium

sinus coronarius (noun)	coronary sinus (noun)
a short sinus receiving most of the veins of the heart; empties into the right atrium	a short sinus receiving most of the veins of the heart; empties into the right atrium