inner ear vs internal ear

inner ear and internal ear both are nouns.

Word	Noun	Adjective	Verb	Adverb
inner ear	Yes	No	No	No
internal ear	Yes	No	No	No

As nouns, inner ear and internal ear are synonyms defined as:

inner ear and internal ear: a complex system of interconnecting cavities; concerned with hearing and equilibrium

Other synonyms of inner ear include labyrinth.

inner ear (noun)	internal ear (noun)
a complex system of interconnecting cavities; concerned with hearing and equilibrium	a complex system of interconnecting cavities; concerned with hearing and equilibrium