By what age should the posterior fontanel be completely closed?

The posterior fontanel, located at the back of an infant’s head, typically closes by the age of 2 to 3 months. This closure is an important aspect of infant growth and development, as it indicates that the skull is forming properly to protect the brain as the child grows. The early closure of the posterior fontanel is part of normal anatomical and physiological changes during the first few months of life.

In contrast, the anterior fontanel, which is located at the top of the head, remains open much longer, usually until about 12 to 18 months. This distinction is important for healthcare professionals to monitor cranial development in infants.