anastomotic vein vs vena

anastomotic vein and vena both are nouns.

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

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

anastomotic vein: either of two communicating veins serving the brain
vena: a blood vessel that carries blood from the capillaries toward the heart

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

anastomotic vein (noun)	vena (noun)
either of two communicating veins serving the brain	a blood vessel that carries blood from the capillaries toward the heart