maxillary vein vs vena

maxillary vein and vena both are nouns.

Word	Noun	Adjective	Verb	Adverb
maxillary vein	Yes	No	No	No
vena	Yes	No	No	No

As nouns, vena is a hypernym of maxillary vein; that is, vena is a word with a broader meaning than maxillary vein:

maxillary vein: posterior continuation of the pterygoid plexus; joins the superficial temporal vein to form the retromandibular vein
vena: a blood vessel that carries blood from the capillaries toward the heart

Other hypernyms of maxillary vein include vein, venous blood vessel.

maxillary vein (noun)	vena (noun)
posterior continuation of the pterygoid plexus; joins the superficial temporal vein to form the retromandibular vein	a blood vessel that carries blood from the capillaries toward the heart