Also known as tentorial sinus or the sinus rectus, is an area within the skull beneath the brain that receives venous blood. The straight sinus receives blood from the superior cerebellar veins and inferior sagittal sinus and drains into the confluence of sinuses.

The straight sinus is situated within the dura mater, where the falx cerebri meets the midline of tentorium cerebelli.

In cross-section it is triangular, contains a few transverse bands across its interior, and increases in size as it proceeds backward.

It forms from the confluence of the inferior sagittal sinus and great cerebral vein.

The straight sinus is an unpaired area beneath the brain which allows blood to drain from the inferior center of the head outwards posteriorly. It receives blood from the inferior sagittal sinus, great cerebral vein, posterior cerebral veins, superior cerebellar veins and veins from the falx cerebri.

Quiñones-Hinojosa, et al. ¹⁾ described a bilateral occipital transtentorial/transfalcine approach for large falcotentorial meningiomas. They ligated and cut the transverse sinus after checking the patency of the occluded sinus, and used permanent aneurysmal clips to ligate the vein of Galen when the straight sinus was occluded. The area above and below the tentorium can provide wide exposure and reduce occipital lobe retraction during prolonged operation times. Moreover, this approach may allow surgeons some form of intraoperative flexibility in terms of their surgical plan.