brachycranial vs brachycephalic

brachycranial is not a noun while brachycephalic is a noun.

Word	Noun	Adjective	Verb	Adverb
brachycranial	No	Yes	No	No
brachycephalic	Yes	Yes	No	No

As adjectives, brachycranial and brachycephalic are synonyms defined as:

brachycranial and brachycephalic: having a short broad head with a cephalic index of over 80

Other synonyms of brachycranial include brachycranic.

brachycranial (noun)	brachycephalic (noun)
	an adult with a short broad head

brachycranial (adjective)	brachycephalic (adjective)
having a short broad head with a cephalic index of over 80	having a short broad head with a cephalic index of over 80