Craniosynostosis is premature closure of the cranial sutures. Causes may be primary or secondary to certain hematologic, metabolic disorders or bone dysplasia and syndromes. The most common is premature closure of the sagittal suture. Plagiocephaly occurs owing to premature closure of one of the coronal sutures.

Differential diagnosis:

It should not be confused with positional plagiocephaly that results from external pressure and from hemimegalencephaly that shows hypertrophy of one cerebral hemisphere (commonly the left) with cortical dysplasia and ipsilateral ventricular dilatation. The overlying calvarium is thickened.