While rare, a baby can be born without a fontanel, or with a prematurely closed fontanel, a condition known as craniosynostosis.
Here's a more detailed explanation:
What are Fontanelles?
Fontanelles, often called "soft spots," are gaps between the bones of a baby's skull. These spaces are covered by a tough membrane and allow the skull to compress slightly during birth, making it easier for the baby to pass through the birth canal. They also provide room for the brain to grow rapidly during infancy. Typically, a baby has two fontanelles: the anterior (on top of the head) and the posterior (at the back of the head). The posterior fontanelle usually closes within a few months after birth, while the anterior fontanelle closes between 9 and 18 months.
Craniosynostosis: When Fontanelles Close Too Early or Are Absent
Craniosynostosis is a condition in which one or more of the cranial sutures (fibrous joints between the skull bones) fuse prematurely. This can lead to an absent or very small fontanelle.
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Types of Craniosynostosis: There are several types, depending on which suture(s) fuse too early.
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Consequences: Premature fusion can restrict brain growth in certain areas, potentially leading to increased intracranial pressure and abnormal head shape.
Signs of Craniosynostosis that Suggest an Absent Fontanelle
Besides the absence of a fontanelle, other signs of craniosynostosis can include:
- A small, hard ridge along the fused suture line.
- An asymmetrical or unusually shaped head.
- Slow or no head growth as the baby ages.
- In some cases, increased intracranial pressure, which can cause symptoms like vomiting, irritability, and developmental delays.
Important Considerations
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It's important to note that a small fontanelle doesn't automatically indicate craniosynostosis. Some babies naturally have smaller fontanelles than others.
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A doctor should evaluate any concerns about a missing or prematurely closed fontanelle. Diagnostic tests, such as a CT scan, may be necessary to confirm the diagnosis and determine the best course of treatment.
In conclusion, although fontanelles are typically present at birth, a baby can be born without one due to craniosynostosis, a condition that requires medical evaluation.
