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FIG 2. A–F, Anatomic relationships of the parasagittal line in a 92-year-old man. The composite representation (A) was traced from serial axial CT images (B–F). Labels as in figure 1. M indicates midline. In A, the curved gray lines surrounding the partes marginales (arrowheads) represent the pars deflections and correspond to the dashed curved lines seen around the partes marginales in figure 1. In the supraventricular sections, the parasagittal line (paramedian lines, P) demarcate the deepest extensions of the medial sulci and separate them from the deepest extensions of the lateral sulci. In the upper sections, multiple transverse sulci show short sharp deflections, which align along the parasagittal line. Note specifically the alignment of the SFS (a) and IOS (o) along the parasagittal line and their alignment with the notches in the precentral sulci (arrows), with the medial aspects of the knobs (asterisks) of the hand-motor areas, and with the inscriptions in the central sulci (d) just medial to the hand-motor areas. The partes marginales (arrowheads), pars deflections (gray pencil lines), and postcentral parentheses lie medial to the parasagittal line. In this composite tracing, the inferiorly situated occipital sulci superimpose upon the superior parietal lobules (S)
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