sternocleidomastoid vein vs vena sternocleidomastoidea

sternocleidomastoid vein and vena sternocleidomastoidea both are nouns.

Word	Noun	Adjective	Verb	Adverb
sternocleidomastoid vein	Yes	No	No	No
vena sternocleidomastoidea	Yes	No	No	No

As nouns, sternocleidomastoid vein and vena sternocleidomastoidea are synonyms defined as:

sternocleidomastoid vein and vena sternocleidomastoidea: drains the sternocleidomastoid muscle; empties into the internal jugular vein

sternocleidomastoid vein (noun)	vena sternocleidomastoidea (noun)
drains the sternocleidomastoid muscle; empties into the internal jugular vein	drains the sternocleidomastoid muscle; empties into the internal jugular vein