A Soft Spot for Baby

Question:

What is a baby's soft spot?

Answer:

When babies are born, their skull bones have not yet fused. This incomplete closure benefits newborns by allowing them to squeeze more easily through the birth canal, and it later accommodates brain growth. At birth, there are usually two "soft spots" present: the "anterior fontanelle," located toward the front of the head, and the "posterior fontanelle," located toward the back of the head. The posterior fontanelle measures between 1 and 2 centimeters at birth and normally closes during the first four months of life. The anterior fontanelle is larger, measuring between 4 and 6 centimeters at birth. Although it is normal for it to close as early as the age of four months or as late as 26 months, 90% close between the ages of seven and 19 months.

These measurements, as well as a child's head circumference, should be followed closely during the first few years of life. Poor head growth and subsequent early closure of the soft spots are worrisome, as they may indicate abnormal brain development. But even if the soft spot is closing "early," as long as the child's head is continuing to grow and he or she is meeting developmental milestones, the pediatrician will only need to follow the child?s progress with regular checkups.

Poor head growth is different from craniosynostosis, a rare condition caused by the premature closure of one or more of the spaces between the skull bones. These sites at which the skull bones fuse are referred to as "cranial sutures." If a cranial suture closes too early, brain growth is restricted in that area. Consequently, the remaining sutures that are open compensate for the early closure, allowing the brain to develop normally, but the result is a misshapen head. Isolated closure of a single suture usually results only in cosmetic changes. However, early fusion of several sutures may cause significant deformities of the face and skull, impair brain growth, lead to increased pressure within the skull, and in severe cases, result in death. Since brain growth occurs quickly during the first year of life, craniosynostosis should be diagnosed early and children should be promptly referred to a neurosurgeon for treatment. The initial surgery is usually performed between the ages of two and nine months to achieve the best cosmetic result and to ensure proper brain growth. The extent and number of surgeries depend on the severity of the malformation.

If your sister's pediatrician suspected craniosynostosis, he should have immediately referred her to a neurosurgeon. It is more likely that he was somewhat overzealous in his concern regarding "premature" closure of your niece's soft spot. You might want to get a second opinion.