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What Is Craniosynostosis?

Craniosynostosis is when one or more seams between bones in a child's skull close too soon. When this happens, the skull can't grow properly, and develops a different shape.

What Happens in Craniosynostosis?

Babies' skulls are made of several bones that fit together like a puzzle. At birth, the borders between the bones (called cranial sutures) are not yet solid. This lets the skull expand, leaving the "soft spot" (or fontanelle).

Normally, cranial sutures:

  • flex and squeeze together a little, so that a baby's head can fit through the mother's pelvis during childbirth
  • let the skull expand to make room for the baby's rapidly growing brain
  • remain open until the third decade of life (when someone is in their twenties). The mid-forehead suture (the metopic suture) is the only exception, and it normally closes within the first year of life.

But in craniosynostosis (kray-nee-oh-sin-oss-TOE-sis), one or more sutures close too soon, either before birth or within a few months after. Craniosynostosis that's not corrected can cause pressure inside the skull (intracranial pressure). If it’s not treated, the increased intracranial pressure can lead to developmental problems, headaches, brain damage, or blindness.