Introduction: Cerebral veins drain the blood into the dural sinuses, which are endothelium-lined channels without valves and enclosed in the leaves of the dura mater. The superior group comprises the superior and inferior sagittal sinus, and the straight, transverse, and sigmoid sinuses superficial veins drain into the superior sagittal and transverse sinuses, and the deep cerebral veins into the straight and transverse sinuses. The confluence of the sinuses (torcular Herophili) results from the junction of superior sagittal, straight, and transverse sinuses and is often asymmetrical. The inferior group drains the basal and medial parts of the undersurface of the brain, the orbits, and the sphenoparietal sinus and collects at the cavernous sinus. Aim of the Study: To assess the drainage pattern in venous sinuses within the tentorium cerebelli in 100 cases of the autopsy. Materials and Methods: In this study, 100 human cadaveric brains of both male and female that underwent autopsy within 12-48 hrs after death were studied in the year 2016-2018 in Department Of Neurosurgery, Government Mohan Kumaramangalam Medical College, Salem. Skullcap was opened in a circular manner. The frontal lobes were lifted after opening the dura mater and the anterior falx was cut. The brain stem was cut axially just above the level of tentorial incisura. Results: In this study, the group - 1: 22 (32%) sinuses were typed A, 40 (58%) sinuses were type B, 7 (10%) sinuses were type C, among the Group 1 sinuses. Of these 69 sinuses, 6 sinuses which were longer in size occupying a small portion of the medial part of middle one-third of tentorium cerebelli along with its course in entire medial one-third of tentorium cerebelli. Among these sinuses, two sinuses were on the right side and eight sinuses were on the left side. All of these sinuses were smaller in size. No branching pattern was observed in Group 2 sinuses. All of these sinuses were observed to drain into the middle one-third of the transverse sinus. The tentorial sinuses of Group 3 were drained into lateral one-third of transverse sinus or to the junction of the transverse sinus and superior petrosal sinus. Venous ring pattern was occupying the entire posterior portion of tentorium cerebelli. This venous ring was bilateral in two cadavers and unilateral in four cadavers. Conclusion: These sinuses serve as important collateral channels when the straight sinus or torcular herophili is occluded by pathological processes. They also play an important role in several vascular and congenital malformations of the brain. 

Keywords: Tentorial Sinuses; Drainage Pattern; Sphenoparietal Sinus; Cavernous Sinus