venography vs arthrography

venography and arthrography both are nouns.

Word	Noun	Adjective	Verb	Adverb
venography	Yes	No	No	No
arthrography	Yes	No	No	No

As nouns, arthrography is a hypernym of venography; that is, arthrography is a word with a broader meaning than venography:

venography: roentgenographic examination of veins
arthrography: roentgenographic examination of a joint after injection of radiopaque contrast medium; produces an arthrogram

venography (noun)	arthrography (noun)
roentgenographic examination of veins	roentgenographic examination of a joint after injection of radiopaque contrast medium; produces an arthrogram