noun which may take the genitive case particle 'no'
intracranial; endocranial
Medical term meaning 'inside the skull'. Used attributively with の, as in 頭蓋内出血 (intracranial hemorrhage).
頭蓋内出血は緊急の治療が必要です。
Intracranial hemorrhage requires emergency treatment.
頭蓋外 means 'extracranial', the opposite of 頭蓋内.
Compound of 頭蓋 (skull, cranium) + 内 (inside). A straightforward medical term.