The straight sinus, also known as tentorial sinus or the sinus rectus, is an area within the skull beneath the brain. It receives blood from the inferior sagittal sinus and the great cerebral vein, 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.^[1] It forms from the confluence of the inferior sagittal sinus and the great cerebral vein.^[1][2] It may also drain blood from the superior cerebellar veins and veins from the falx cerebri.^[1] In cross-section, it is triangular, contains a few transverse bands across its interior, and increases in size as it proceeds backward.^{[citation needed]} It is usually around 5 cm long.^[2]

The straight sinus 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.^[1]

• Tentorium cerebelli from above.
• Straight sinus

• Dural venous sinuses