Which statement about fontanel closures is true?

• A. Posterior fontanel closes by 2 months.
• B. Anterior fontanel closes by 18 months.
• C. Posterior fontanel closes by 18 months.
• D. Anterior fontanel closes by 2 months.

Answer: (A)

Understanding fontanel closures helps you assess infant skull development. The posterior fontanel, a small triangular soft spot at the back of the head, closes earlier in life. It typically shuts around two months of age, sometimes a little later but usually within the first couple of months. The anterior fontanel, by contrast, is larger and remains open longer, generally closing around 12 to 18 months, with some variability up to about 18 to 24 months in different references.

So the statement that the posterior fontanel closes by about two months aligns with the standard timing and is the most consistently observed fact. The anterior fontanel’s timing is broader and not as fixed, which is why the posterior claim stands out as true and most specific.