'posterior-to-anterior' is a compound formed from the Latin-derived adjectives 'posterior' and 'anterior'; 'posterior' comes from Latin 'posterus' meaning 'coming after' (relative in time or position), and 'anterior' comes from Latin 'ante' meaning 'before' (in time or position).

'posterior' and 'anterior' entered English via Latin (and through Old French/Medieval Latin influences) as comparative/adjectival forms and were used in English from Middle English onward; the hyphenated compound 'posterior-to-anterior' is a modern descriptive formation used in technical contexts (especially anatomy and radiography).

Originally 'posterior' and 'anterior' primarily conveyed temporal notions ('coming after' and 'coming before'); over time their spatial senses ('back' and 'front' of the body) became standard in anatomy and related fields, which is the sense used in this compound.