Which of the following is the last fontanelle to close

The anterior fontanelle is the last fontanelle to close. It closes around 18-24 months of age. Fontanelle of the skull: The anterior fontanelle is present between the two frontal and two parietal bones. It closes around 18-24 months. The junction is marked by bregma where the coronal and saggital sutures meet. The posterior fontanelle is present between the junction of the sagittal and lambdoid suture and closes at around 2-3 months of bih. The sphenoid fontanelle corresponds to the pterion and also closes at around 2-3 months of bih. The mastoid fonatanelle closes around at the end of the first year. Ref: Gray&;s Anatomy 41st edition Pgno: 418