Which sequence correctly describes the CSF flow pathway?

• A. Lateral ventricles → interventricular foramen of Monro → third ventricle → cerebral aqueduct → fourth ventricle → subarachnoid space.
• B. Lateral ventricles → third ventricle → fourth ventricle → interventricular foramen → subarachnoid space.
• C. Subarachnoid space → ventricles.
• D. Fourth ventricle → spinal canal → lateral ventricles.

Answer: (A)

The flow of CSF through the ventricular system proceeds in a typical directional sequence: CSF is produced in the choroid plexus of the lateral ventricles and moves through the interventricular foramen (foramen of Monro) into the third ventricle, then through the cerebral aqueduct into the fourth ventricle, and from there into the subarachnoid space (via the foramina of Luschka and Magendie) to circulate around the brain and spinal cord. The sequence described—lateral ventricles → Monro foramen → third ventricle → cerebral aqueduct → fourth ventricle → subarachnoid space—follows this path exactly, making it the correct description. The other options mix up the order or imply flow in the wrong direction, such as moving from the subarachnoid space back into the ventricles or starting to spinal canal before ventricle flow, which isn’t how CSF normally travels.