Fig 4.

Anatomic preparation showing a case of bilateral hypoplastic rostral SSS. Note that the large compensatory parasagittal frontal veins (arrowheads) are truly pia-arachnoid veins and not dural venous sinuses, in keeping with the CTV and DSA findings reported in our study. There is a transition zone (arrows) in which these veins become thickened before entering the middle third of the SSS in the vicinity of the coronal suture. These findings are to be distinguished from the observations reported by Kaplan and Browder,¹³ in which the compensatory venous occurred by way of intradural venous drainage channels coursing parallel to the midsagittal plane, strongly suggesting a duplication of the rostral SSS rather than true hypoplastic rostral SSS.