Cisterna magna

The cisterna magna (or cerebellomedullary cistern) is a large cistern between the cerebellum and medulla. It lies between the cerebellum and the dorsal surface of the medulla.

As with all cisterns of the brain, this cistern is an opening in the subarachnoid space created by the separation of the arachnoid and pia mater.

The cisterna magna (cerebellomedullary cistern) allows CSF to drain via the lateral and median apertures. The pontine cistern is between the pons and the medulla. The interpeduncular cistern is a large space between the cerebral peduncles.