Asymmetries of the cerebral hemispheres on computed tomograms.

Numerous cerebral asymmetries are shown on cerebral computed tomography (CT). Those seen most commonly are: (a) the left occipital pole is frequently wider and protrudes further posteriorly than the right; (b) the right frontal area often measures wider than the left, and the right frontal pole usually protrudes either as far forward as the left or extends beyond the left; and (c) the calcified glomus of the left lateral ventricle commonly lies posterior to that of the right when there is posterior protrusion of the left occipital pole beyond the right. The above hemispheral asymmetries are more common in right handed individuals. Hemispheral asymmetries tend to be less striking in left handed individuals, but widening of the left frontal and right occipital regions is more common in left handers than right handers. In both right and left handers, the central portion of the right hemisphere is frequently wider than the left; the pineal therefore often lies slightly to the left of the midline in normal brains. A study of cerebral asymmetries should help in the detection of early mass lesions and may also help in the study of hemispheral specialization for behavioral function.