Tentorial sinuses are constant venous channels that have been divided into medial and lateral groups 1) 2) 3).

These sinuses are located on each half of the tentorium. The medial tentorial sinuses are responsible for the venous drainage of the superior cerebellar surface. The medial tentorial sinuses empty into the straight sinus and transverse sinus confluence

1)
Oka K, Rhoton AL Jr, Barry M, Rodriguez R. Microsurgical anatomy of the superficial veins of the cerebrum. Neurosurgery 1985;17:711–748
2)
Sakata K, Al-Mefty O, Yamamoto I. Venous consideration in petrosal approach: microsurgical anatomy of the temporal bridging vein. Neurosurgery 2000;47:153–161
3)
Rhoton AL. The cerebral veins [suppl]. Neurosurgery 2002;51:S159–S205