rectus medialis vs eye muscle

rectus medialis and eye muscle both are nouns.

Word	Noun	Adjective	Verb	Adverb
rectus medialis	Yes	No	No	No
eye muscle	Yes	No	No	No

As nouns, eye muscle is a hypernym of rectus medialis; that is, eye muscle is a word with a broader meaning than rectus medialis:

rectus medialis: the ocular muscle whose contraction turns the eyeball medially
eye muscle: one of the small muscles of the eye that serve to rotate the eyeball

Other hypernyms of rectus medialis include ocular muscle.

rectus medialis (noun)	eye muscle (noun)
the ocular muscle whose contraction turns the eyeball medially	one of the small muscles of the eye that serve to rotate the eyeball