Which fontanelle closes earliest in infancy?

Which fontanelle closes earliest in infancy?

• A. Anterior fontanelle
• B. Posterior fontanelle
• C. Both close at the same time
• D. None of the fontanelles close

Answer: (D)

Fontanelles are soft spots on the infant’s skull that allow for brain growth and skull expansion during the first years of life. The one at the back of the head, the posterior fontanelle, is small and closes earliest—usually by about 2 to 3 months of age. The larger anterior fontanelle at the top front remains open much longer and typically closes around 12 to 18 months (up to 24 months in some children). So the earliest closing fontanelle is the posterior one. Saying that none of the fontanelles close isn’t accurate, since the posterior one typically closes within the first few months.

Fontanelles are soft spots on the infant’s skull that allow for brain growth and skull expansion during the first years of life. The one at the back of the head, the posterior fontanelle, is small and closes earliest—usually by about 2 to 3 months of age. The larger anterior fontanelle at the top front remains open much longer and typically closes around 12 to 18 months (up to 24 months in some children). So the earliest closing fontanelle is the posterior one. Saying that none of the fontanelles close isn’t accurate, since the posterior one typically closes within the first few months.