Right-side head radical — originally pictured a head set on a body with three lines of hair on top, now flattened into the simplified six-stroke
页. The indexing radical here, supplying the meaning:
颅 names the skull or cranium. The radical anchors
颅 in the head-and-face family along with
顶 crown,
颈 neck,
额 forehead,
颊 cheek.