musculus pectoralis vs pectoral muscle

musculus pectoralis and pectoral muscle both are nouns.

Word	Noun	Adjective	Verb	Adverb
musculus pectoralis	Yes	No	No	No
pectoral muscle	Yes	No	No	No

As nouns, musculus pectoralis and pectoral muscle are synonyms defined as:

musculus pectoralis and pectoral muscle: either of two large muscles of the chest

Other synonyms of musculus pectoralis include pecs, pectoral, pectoralis.

musculus pectoralis (noun)	pectoral muscle (noun)
either of two large muscles of the chest	either of two large muscles of the chest