When a baby is born, its skull is not the solid single piece of bone it will become later in life. To allow the baby to pass through the birth canal, as well as to allow for additional brain growth, the skull is initially separated into several different parts. While these separations are necessary in early life, they make an infant's head particularly fragile.
An infant's skull is made up of six bones. During the first few years of life, these bones are not fused but held together by a type of stretchy tissue called cranial sutures. There are two spaces in the skull that are not covered by bone but only by the cranial sutures. These spaces are called fontanels, or soft spots.
During the first two years of life, the separate bones of the skull slowly begins to fuse together. The fusing process occurs over multiple years, because the brain is still growing, and will not reach adult size until approximately age seven. However, the two large soft spots on an infants head are both closed by the time the child reaches age three.
One of the main concerns dealing with infant skull development is the potential for the skull to become flattened on one side. This can occur if the child spends the majority of her time in one position--for infants, this is often on their back. Flatness can often be counteracted by making sure the infant is spending time laying in different positions. In more severe cases, head-shaping helmets or headbands are used.
Craniosynostosis is a birth defect that involves the development of an infant's skull. When this defect is present, one or more of the soft spots in the skull close before they should. This can cause pressure in the skull and, in some cases, impede brain development. Craniosynostosis is often treated with surgery to reopen the fused area. In less severe cases, a head-shaping helmet is occasionally used in place of surgery.
Because a child's skull is particularly fragile during the first two to three years of life, parents should be contentious and careful concerning their child's head. Infants should be repositioned frequently, though when sleeping should always be placed on their backs. Parents should also thoroughly research car seats before making a purchase to ensure their child will be as safe as possible in the event of an accident.