When does the anterior fontanel typically close in infants?

The closure of the anterior fontanel in infants is an important developmental milestone. Typically, the anterior fontanel, which is the soft spot on the top of a baby's head, closes between 18 to 24 months of age. This timeframe is significant because it marks the period when the brain has grown sufficiently and the skull has developed enough to provide protection and support.

This closure is part of the natural process of head growth and development in infants, and it allows for the skull to harden and take a more defined shape as the child grows. Monitoring the timing of fontanel closure can be an important aspect of assessing a child's growth and development, helping healthcare providers ensure that everything is proceeding normally.

In contrast, the other timeframes provided in the options don't reflect the typical development pattern for the anterior fontanel. Closure times earlier than 18 months could indicate premature closure or other developmental issues, while closure times later than 24 months may also warrant further assessment. Thus, 18 to 24 months is the most accurate range for the closure of the anterior fontanel.