What is "falx cerebelli"

n. (context medicine English) A fold of the dura mater that divides the hemispheres of the cerebellum.

The falx cerebelli is a small sickle shaped fold of dura mater, projecting forwards into the posterior cerebellar notch as well as projecting into the vallecula of the cerebellum between the two cerebellar hemispheres. The name comes from the Latin word falx meaning "curved blade or scythe" and cerebellum meaning "brain". Its base is attached, above, to the under and back part of the tentorium cerebelli; its posterior margin, to the lower division of the vertical crest on the inner surface of the occipital bone. The falx cerebelli generally lies somewhere between 2.8 and 4.5 cm in length and is approximately 1–2 mm thick.