platysma vs facial muscle

platysma and facial muscle both are nouns.

Word	Noun	Adjective	Verb	Adverb
platysma	Yes	No	No	No
facial muscle	Yes	No	No	No

As nouns, facial muscle is a hypernym of platysma; that is, facial muscle is a word with a broader meaning than platysma:

platysma: either of two broad muscles located on either side of the neck and innervated by the facial nerve; extends from lower jaw to clavicle and is involved in moving the mouth and jaw
facial muscle: any of the skeletal muscles of the face

platysma (noun)	facial muscle (noun)
either of two broad muscles located on either side of the neck and innervated by the facial nerve; extends from lower jaw to clavicle and is involved in moving the mouth and jaw	any of the skeletal muscles of the face