What is Craniosynostosis?
Craniosynostosis is a birth defect in which the bones in a baby’s skull join together too early. This occurs before the baby’s brain is fully formed. As the baby’s brain grows, the skull can become more misshapen. In a typical baby, the spaces between the skull bones are filled with flexible material known as sutures. These sutures allow the skull to grow as the baby’s brain grows. Around two years of age, a child’s skull bones begin to join together because the sutures transform into bone. This process is known as the suture “closing.”
In a baby with craniosynostosis, one or more of the sutures closes prematurely. This can limit or slow the growth of the baby’s brain.
Types of Craniosynostosis
The types of craniosynostosis depend on which sutures join together too early:
Sagittal synostosis: The sagittal suture runs along the top of the head, from the baby’s soft spot near the front of the head to the back of the head. When this suture closes too early, the baby’s head will grow long and narrow (scaphocephaly). It is the most common type of craniosynostosis.
Coronal synostosis: The right and left coronal sutures run from each ear to the sagittal suture at the top of the head. When one of these sutures closes too early, the baby may have a flattened forehead on the side of the skull that closed early (anterior plagiocephaly). The baby’s eye socket on that side might also be raised up, and his or her nose could be pulled toward that side. This is the second most common type of craniosynostosis.
Bicoronal synostosis: This type of craniosynostosis occurs when the coronal sutures on both sides of the baby’s head close too early. In this case, the baby’s head will grow broad and short (brachycephaly).
Lambdoid synostosis: The lambdoid suture runs along the backside of the head. If this suture closes too early, the baby’s head may be flattened on the back side (posterior plagiocephaly). This is one of the rarest types of craniosynostosis.
Metopic synostosis: The metopic suture runs from the baby’s nose to the sagittal suture at the top of the head. If this suture closes too early, the top of the baby’s head shape may look triangular, meaning narrow in the front and broad in the back (trigonocephaly). This is one of the rarest types of craniosynostosis.
