metatarsus vs metatarsal

metatarsus and metatarsal both are nouns.

Word	Noun	Adjective	Verb	Adverb
metatarsus	Yes	No	No	No
metatarsal	Yes	Yes	No	No

metatarsus (noun)	metatarsal (noun)
the skeleton of the human foot between the toes and the tarsus; the corresponding part of the foot in birds or of the hind foot in quadrupeds	any bone of the foot between the ankle and the toes

metatarsus (adjective)	metatarsal (adjective)
	of or relating to the metatarsus