New parents often feel a mix of wonder and apprehension when observing the delicate soft spots on their baby’s head. These areas, known as fontanelles, are a normal and important aspect of infant anatomy. They are not as fragile as they might seem and play a significant role in a baby’s healthy development. Understanding fontanelles and their care can ease parental concerns and build confidence in nurturing a newborn.
Understanding Soft Spots
Soft spots are spaces between the bones of a baby’s skull that have not yet fused together. These gaps are covered by a tough, protective membrane, not directly by the brain itself. The skull of a newborn consists of several separate bony plates, including frontal, parietal, and occipital bones, which are connected by fibrous joints called sutures.
Where to Find Them
A newborn has several fontanelles, but two are most easily felt and commonly discussed. The anterior fontanelle, located on the top-front part of the head, is diamond-shaped and can measure approximately 0.6 to 3.6 centimeters at birth. The posterior fontanelle is smaller, triangular, and positioned at the back of the head, generally about 0.5 centimeters in diameter, similar to a pencil eraser. When gently touched, a normal fontanelle should feel flat or slightly curved inward and may even show a subtle pulsation.
Why Babies Have Them
Fontanelles serve two primary functions that are important for a baby’s well-being. First, they allow the skull bones to overlap and compress during childbirth, enabling the baby’s head to navigate through the narrow birth canal more easily. This flexibility helps prevent injury to the baby’s brain during delivery. Second, these soft spots accommodate the rapid growth of the baby’s brain during the first year of life. A baby’s brain grows considerably, and the fontanelles provide the necessary space for this expansion without putting pressure on the developing brain.
Caring for Soft Spots and When to Consult a Doctor
Parents often worry about damaging a baby’s soft spots, but they are more resilient than they appear due to the underlying protective membrane. Gentle handling during routine activities like washing hair, combing, or dressing the baby is perfectly safe. However, significant pressure or impact should always be avoided.
While generally robust, certain changes in a fontanelle’s appearance can signal a medical concern. A sunken fontanelle can indicate dehydration; other signs might include fewer wet diapers, dry mouth, or reduced alertness. Conversely, a bulging fontanelle can be a sign of increased pressure inside the skull. This could be associated with conditions such as infection, fluid buildup, or bleeding, and requires immediate medical attention. While temporary bulging can occur during crying or vomiting, a persistent bulge warrants a prompt medical evaluation.
When Soft Spots Close
The closure of fontanelles is a gradual process that occurs as the skull bones harden and fuse. The posterior fontanelle typically closes first, usually between 1 to 3 months of age. In some cases, it may even be closed at birth.
The anterior fontanelle takes longer to close. It generally fuses between 7 and 18 months of age, though it can remain open up to 24 months. This timeline allows for continued brain growth during an important developmental period. Individual variations exist, and a healthcare provider will monitor the fontanelles during routine check-ups to ensure normal development.