The cisterna magna (also known as the cerebellomedullary cistern) is the largest of the CSF -filled subarachnoid cisterns. Gross anatomy The cisterna magna is located between the cerebellum and the dorsal surface of the medulla oblongata at and above the level of the foramen magnum.

Cerebellomedullary cisterns are basal cisterns located laterally and posteriorly around the medulla, between it and the adjacent cerebellum.