<prompt> Anterior fontanelle closes at ___3months12months12-18months3years  <response>: The posterior fontanelle generally closes 2 to 3 months after bih; The sphenoidal fontanelle is the next toclose around 6 months after bih; The mastoid fontanelle closes next from 6 to 18 months after bih; and. The anterior fontanelle is generally the last to close between 10-24 months. Ref : Nelson paediatrics Chapter : Growth and development 