Functional Cerebral Venous Anatomy: A Perspective on Venous Collaterals Part II, Infratentorial Venous System.

The infratentorial veins are densely packed in a smaller space compared to the supratentorial veins and have many variations, such as disconnections and anastomoses. Knowledge of the functional venous anatomy of the posterior fossa is becoming increasingly important in neurointerventional procedures. The basic brainstem veins are longitudinal and transverse veins. The venous drainage of the brainstem and cerebellum follows 3 paths: superior (Galenic), anterior (petrosal), and posterior (torcular). Knowledge of the basic venous anatomy of the brainstem and cerebellum is essential for understanding the routes and patterns of venous drainage under pathological conditions, particularly in arteriovenous shunts. This review describes posterior fossa venous development and the functional venous anatomy of the posterior fossa, mainly the veins of the brainstem, cerebellum, and the emissary veins.