The fluid-filled space located between the undersurface of the cerebellum and the medulla oblongata is the?

The fluid-filled space located between the undersurface of the cerebellum and the medulla oblongata is the?

• A. Cisterna magna
• B. Fourth ventricle
• C. Interpeduncular cistern
• D. Pontine cistern

Answer: (A)

In the posterior fossa, the space between the undersurface of the cerebellum and the medulla oblongata is the cisterna magna, a large subarachnoid cistern that sits just below the cerebellum and behind the medulla. It holds CSF and communicates with the fourth ventricle above via the pathways that connect ventricular CSF to the subarachnoid space. The fourth ventricle itself is a ventricular cavity within the brainstem, not this cistern. The interpeduncular cistern lies in front of the midbrain, and the pontine cistern surrounds the pons, so neither matches the location described.

In the posterior fossa, the space between the undersurface of the cerebellum and the medulla oblongata is the cisterna magna, a large subarachnoid cistern that sits just below the cerebellum and behind the medulla. It holds CSF and communicates with the fourth ventricle above via the pathways that connect ventricular CSF to the subarachnoid space. The fourth ventricle itself is a ventricular cavity within the brainstem, not this cistern. The interpeduncular cistern lies in front of the midbrain, and the pontine cistern surrounds the pons, so neither matches the location described.