The lateral ventricles communicate with the third ventricle through which foramen?

• A. Foramen of Monro
• B. Foramen of Magendie
• C. Cerebral aqueduct
• D. Median aperture

Answer: (A)

The main idea is how CSF flows between the brain’s ventricles. The lateral ventricles connect to the third ventricle through the foramen of Monro (interventricular foramen). This tiny opening lets CSF move from each lateral ventricle into the single midline third ventricle, continuing onward through the cerebral aqueduct to the fourth ventricle and then out to the subarachnoid space.

The other openings are parts of later stages: the foramen of Magendie is the median aperture of the fourth ventricle (an outlet to the subarachnoid space), the lateral and median apertures are not the path linking the lateral ventricles to the third, and the cerebral aqueduct connects the third to the fourth ventricle, not the lateral to the third. So the correct foramen is the foramen of Monro.