pigs' feet vs pigs' knuckles

pigs' feet and pigs' knuckles both are nouns.

Word	Noun	Adjective	Verb	Adverb
pigs' feet	Yes	No	No	No
pigs' knuckles	Yes	No	No	No

As nouns, pigs' feet and pigs' knuckles are synonyms defined as:

pigs' feet and pigs' knuckles: feet or knuckles of hogs used as food; pickled or stewed or jellied

pigs' feet (noun)	pigs' knuckles (noun)
feet or knuckles of hogs used as food; pickled or stewed or jellied	feet or knuckles of hogs used as food; pickled or stewed or jellied