Why Do Babies Have Soft Spots on Their Heads?

Medical personnel call a baby's soft spots "fontanelles." A newborn has two soft spots that are both along the center line of the head from front to back. The soft spot on top of the baby's head is called the anterior fontanelle, and the soft spot on the back of the head is called the posterior fontanelle.

Definitions

According to the University of Maryland Medical Center, babies are born with six skull bones that have not fused. Fontanelles are the spaces between those bones. Fontanelles contain the cranial sutures, which are the bands of elastic tissue that hold the skull bones together.

Soft Spots During Childbirth

The soft spots aid in the birth of the baby. During childbirth, the flexibility of the cranial sutures allows the baby's skull bones to overlap and make the head smaller. This process gives the head easier passage through the birth canal while protecting the brain's delicate tissues.

Soft Spots and Brain Growth

The soft spots in a baby's skull allow the skull to expand as the baby's brain grows during infancy and early childhood. If the soft spots close too soon, it can lead to problems with the brain's development. That condition is called craniosynostosis.

Closure

The anterior fontanelle usually closes when the baby is one to two months old. The posterior fontanelle usually closes between nine and 18 months of age.

Complications

Fontanelles are usually soft and somewhat indented. Bulging fontanelles can be an indication of increased pressure inside the head, which is called hydrocephalus. A baby with bulging fontanelles should be examined by a doctor very quickly.

References

• University of Maryland Medical Center
• Craniosynostosis