Bifid postcentral gyrus sign

The bifid postcentral gyrus sign, also known as the pars deflection sign, is a landmark useful for identifying the central sulcus on cross-sectional imaging.

The medial aspect of the postcentral gyrus splits in two before meeting the interhemispheric fissure. The two legs straddle the pars marginalis of the cingulate sulcus. The white matter that surrounds the pars marginalis is also known as the pars deflections. The central sulcus is the next more anterior sulcus.