Craniosynostosis occurs due to premature fusion of

Craniosynostosis is the premature fusion of one or more cranial sutures, either major (e.g. metopic, coronal, sagittal and lambdoid) or minor (frontonasal, temporosquamosal, and frontosphenoidal). Cranial sutures normally fuse during early childhood, staing with the metopic suture (beginning at 2 months), followed by sagittal, coronal and lambdoid sutures (22-26 months), such that the frontonasal and frontozygomatic sutures close last (68-72 months). Premature fusion restricts the growth of the skull perpendicular to the affected suture. Compensatory skull growth occurs parallel to the affected suture in order to accommodate the growing brain. The resulting skull deformity is termed as scaphocephaly, plagiocephaly or trigonocephaly based on the suture involved. Cloverleaf skull deformity is caused by the fusion of multiple sutures and is associated with hydrocephalus. Patients with tower skull or acrocephaly have combined sagittal, coronal and lambdoid synostosis, often as pa of Ape or Crouzon syndrome. Oxycephaly or turricephaly refers to a tall cranium resulting from delayed repair of brachycephaly and is often syndromic.