Divided parietal bone in plagiocephaly.

Supernumerary cranial sutures represent a rare cause of plagiocephaly. In the case of an extra suture dividing the parietal bone, the presenting features are often inconsistent with the typical presentation of deformational or synostotic plagiocephaly. Disagreement exists as to how the presence of this suture affects the shape of the skull. We present a case of a supernumerary suture in the parietal bone leading to plagiocephaly and discuss the role this suture plays in cranial growth.