When a child walks in the clinic with a unilateral frontal flattening, it is usually associated in our minds with unilateral coronal synostosis. While the latter might be the most common cause of anterior plagiocephaly, it is not the only one. A patent coronal suture will force us to consider other etiologies, such as deformational plagiocephaly, or synostosis of another suture. To understand the mechanisms underlying this malformation, the development and growth of the skull base must be considered.