Some of the asymmetries noted in cerebral computerized transaxial tomography (CTT) studies are reflected in the shape of the skull resulting most often in backward protrusion of the occipital bone on the left and a less striking forward protrusion of the right frontal bone. Asymmetries are less marked in left-handed individuals but the opposite features, i.e. forward protrusion of the left frontal bone and posterior protrusion of the right occipital bone, are more frequent in left handers than in right handers.