A nurse is measuring the head circumference of a 6-month-old infant.

The nurse notes that the anterior fontanel is 4 cm in size and the posterior fontanel is closed.

How should the nurse interpret these findings?

The mother should avoid touching the fontanelles because they are very sensitive.

This statement indicates a need for further teaching because it is a misconception.The fontanelles are not sensitive and can be gently touched and washed without causing any harm to the infant.

Choice A is correct because the fontanelles should be gently washed and dried when bathing the baby to prevent infection.

Choice B is correct because signs of bulging or sunken fontanelles can indicate increased or decreased intracranial pressure, which requires medical attention.

Choice D is correct because the fontanelles usually close by 18 months of age, but some variation is normal.

The fontanelles are soft spots on a baby’s head that have two main functions:

• They allow forrapid growth of the brainduring infancy

• They allow forpassage of the head through the birth canalby enabling the bony plates of the skull to flex

Choice A is wrong because the fontanelles do not allow for passage of blood from the scalp to the brain.The blood supply to the brain is provided by the internal carotid and vertebral arteries, which enter the skull through different openings

The fontanelles also allow forassessment of hydration statusandintracranial pressurein infants by palpating their size and shape.A sunken fontanelle may indicate dehydration, while a bulging fontanelle may indicate increased pressure within the skull