The skull is divided into the vault, base, and face. The vault forms the dome-shaped upper part and contains five bones: the occipital, two parietal, and two frontal bones. Sutures form where bones meet, and fontanels occur where sutures intersect. There are four sutures - lambdoidal, sagittal, coronal, and frontal - and two fontanels - anterior and posterior. Landmarks include the sinciput, occiput, fontanels, vertex, and mentum. Key skull diameters are biparietal, bitemporal, suboccipitobregmatic, and suboccipitofrontal.