Figure 6. Basal dural sinuses. Anteroposterior MIP image from contrast-enhanced MR venography, with the superficial and deep veins removed for better visualization, shows the cavernous sinus complex (1) and, connecting the lateral dural sinuses with the cavernous sinus, the superior petrosal sinuses (2), which arise from the junction of the transverse and sigmoid sinuses and extend along the petrous ridge, and the inferior petrosal sinuses (3), which arise from the distal portion of the sigmoid sinus or jugular bulb and extend along the clivus. Also visible are the superficial middle cerebral vein (sylvian vein) (4), which in this case extends into the cavernous sinus, and the emissary veins and occipital venous plexus complex (5).