Anatomy This is an interventricular foramen through which lateral ventricles open into 3rd ventricle: A Foramen monro. B Foramen of magendi. C Foramen of luschka. D Foramen caecum. 💡 Explanation This is an interventricular foramen through which lateral ventricles open into 3rd ventricle: ✓ Correct Answer: A. Foramen monro.