What is The widest portion of the skull?

The widest portion of the skull is called the parietal bone. It forms the upper and lateral sides of the cranium and is one of the four paired bones that make up the calvaria (the rounded upper part of the skull). The parietal bones meet at the midline of the skull and are joined together by the sagittal suture. They also articulate with the frontal bone anteriorly, the temporal bone inferiorly, and the occipital bone posteriorly.