How many ventricles does the brain possess?

• A. 2
• B. 4
• C. 3
• D. 5

Answer: (B)

Ventricles are spaces within the brain that contain cerebrospinal fluid, arranged as a four-ventricle system. There are two lateral ventricles, one in each cerebral hemisphere, which connect to the midline third ventricle through the foramina of Monro. The third ventricle sits in the diencephalon and communicates with the fourth ventricle via the cerebral aqueduct. The fourth ventricle lies between the brainstem and cerebellum and opens into the subarachnoid space through the foramina of Magendie and Luschka, allowing CSF to circulate around the brain and spinal cord. This configuration—two lateral ventricles plus the third and fourth ventricles—gives the brain four interconnected CSF-filled spaces.