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?

Birth trauma.A cephalohematoma is a collection of blood under the scalp of a newborn that forms a bulge.It is caused by rupture of blood vessels crossing the periosteum due to pressure or trauma on the fetal head during birth.This pressure or trauma may result from a prolonged second stage of labor, instrumental delivery, particularly forceps delivery, ventouse application, or the baby’s head squeezing through the birth canal.

Choice B is wrong because infection is not a cause of cephalohematoma, but a potential complication that may occur in some cases.

Choice C is wrong because dehydration is not a cause of cephalohematoma, but a possible consequence of anemia, which may result from blood loss.

Choice D is wrong because hemorrhage is not a cause of cephalohematoma, but a synonym for bleeding, which is what happens when the blood vessels rupture.

Normal ranges for newborn cephalohematoma are not applicable, as it is an abnormal condition that varies in size and severity.However, most cephalohematomas resolve on their own without intervention within weeks or months.

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