The word "craniosynostosis" refers to a type of birth defect that involves the premature fusion, or closure, of one or more “seams” on a baby’s skull. These seams, or what surgeons call sutures, connect individual skull bones. When these sutures are open, or patent, they allow the skull to expand evenly when the brain grows in infancy. When a suture has closed too early, the skull cannot expand in a uniform fashion. In some cases, this may lead to increased pressure on the brain. This is called elevated intracranial pressure, which can produce signs and symptoms such as headache, irritability, visual changes and developmental delay. Elevated intracranial pressure occurs approximately 13 percent of the time when a single suture is affected, and up to 42 percent of the time when multiple sutures have fused, or closed, early.
Trigonocephaly, a fusion of the forehead suture, is one form of craniosynostosis.