The reflection along the lateral base of the brain as the tentorium cerebelli; it separates the cerebellum from the overlying occipital and postero-medial temporal lobes, and house the transverse sinuses.
Falx cerebelli
The falx cerebelli (not shown here) separates the cerebellar hemispheres.
key anatomic and clinical points
The cranial epidural space is only a potential space because the dura tightly adheres to the skull.
The spinal epidural space is an actual space; it separates the vertebral column, externally, from the dura mater, internally.
As a result, epidural processes, such as infection, hemorrhage, or spread of neoplastic disease occur more commonly in the spinal epidural space than the cranial space.
The meningeal arteries (notably the middle meningeal artery) run between the skull and dura, thus epidural hematoma classically occurs from skull fracture and middle meningeal artery rupture.
Bridging veins connect the brain surface to the superior sagittal venous sinus: they are easily torn within the subdural space and, thus, are the key cause of subdural hematoma.
Physiology of CSF return
Dural venous channels are mostly filled with blood because the rate of CSF production and reabsorption is far slower than the rate of blood entry and reabsorption into and out of the cranial vault (about 20ml per hour).
Arachnoid granulations comprise arachnoid villi, which drain from the subarachnoid space into the venous sinuses.
Neoplastic arachnoid villi cells form meningiomas; thus meningiomas are typically found where there are the greatest concentration of arachnoid villi: at the cerebral convexity (falx cerebri) and base of the skull.