What term describes the area below the tentorium where the cerebellum and brainstem reside?

• A. Supratentorial
• B. Dural Folds
• C. Infratentorial
• D. Choroid Plexus Structures

Answer: (C)

The area below the tentorium cerebelli is described as infratentorial. The tentorium is a fold of dura mater that acts like a ceiling, separating the cerebral hemispheres above from the cerebellum and brainstem below. Because these structures reside beneath that fold, the region they occupy is called infratentorial. This area is also commonly referred to as the posterior fossa. In contrast, the space above the tentorium contains the cerebral hemispheres and is called the supratentorial region. The other options don’t describe this regional division: dural folds is a general description of the membranes themselves, and the choroid plexus structures relate to CSF production within the ventricles, not a regional descriptor.