hypotonus vs hypotonia

hypotonus and hypotonia both are nouns.

Word	Noun	Adjective	Verb	Adverb
hypotonus	Yes	No	No	No
hypotonia	Yes	No	No	No

As nouns, hypotonus and hypotonia are synonyms defined as:

hypotonus and hypotonia: (of muscular tissue) the state of being hypotonic

Other synonyms of hypotonus include hypotonicity.

hypotonus (noun)	hypotonia (noun)
(of muscular tissue) the state of being hypotonic	(of muscular tissue) the state of being hypotonic