dorsum vs body part

dorsum and body part both are nouns.

Word	Noun	Adjective	Verb	Adverb
dorsum	Yes	No	No	No
body part	Yes	No	No	No

As nouns, body part is a hypernym of dorsum; that is, body part is a word with a broader meaning than dorsum:

dorsum: the back of the body of a vertebrate or any analogous surface (as the upper or outer surface of an organ or appendage or part)
body part: any part of an organism such as an organ or extremity

As nouns, body part is a hypernym of dorsum; that is, body part is a word with a broader meaning than dorsum:

dorsum: the posterior part of a human (or animal) body from the neck to the end of the spine
body part: any part of an organism such as an organ or extremity

dorsum (noun)	body part (noun)
the back of the body of a vertebrate or any analogous surface (as the upper or outer surface of an organ or appendage or part)	any part of an organism such as an organ or extremity
the posterior part of a human (or animal) body from the neck to the end of the spine