<prompt> Which of the fontanelle is last to close?Posterior fontanelleAnterior fontanelleMastoid fontanelleSphenoidal fontanelle  <response>: Time of closure of different fontanelle: Posterior fontanelle- 2 to 3 months after bih Anterior fontanelle- 10-24 months after bih Mastoid fontanelle- 6- 18 months after bih Sphenoidal fontanelle- 6months after bih Ref: Nelsons 20th edition, page 2793 