Posterior fontanelle closes between 2 and 3 months of age. Which of the following is the correct range?

Posterior fontanelle closes between 2 and 3 months of age. Which of the following is the correct range?

• A. 3 to 6 months
• B. 2 to 3 months
• C. 9 to 12 months
• D. 6 to 9 months

Answer: (B)

The timing of fontanelle closure helps distinguish normal skull development. The posterior fontanelle is small and closes early, typically by about 2 to 3 months of age as the skull bones fuse. That makes 2 to 3 months the correct range. The other ranges are later than the posterior fontanelle usually closes (the anterior fontanelle stays open longer, often until around 12 to 18 months), so they don’t fit for the posterior fontanelle.

The timing of fontanelle closure helps distinguish normal skull development. The posterior fontanelle is small and closes early, typically by about 2 to 3 months of age as the skull bones fuse. That makes 2 to 3 months the correct range. The other ranges are later than the posterior fontanelle usually closes (the anterior fontanelle stays open longer, often until around 12 to 18 months), so they don’t fit for the posterior fontanelle.