If the third ventricle is dilated, but the fourth ventricle is not, there would then be pathology associated with aqueduct of sylvius.
The part of the brainstem that joins the third and fourth ventricles is known as the cerebral aqueduct. It is situated in the midbrain and encircled by periaqueductal grey matter , with the tectum of midbrain and tegmentum situated anteriorly and posteriorly, respectively.
The main function of the ventricles is to pump blood from the heart into the pulmonary or systemic circulatory systems. Blood flows from the atria into the ventricles during diastole, when the ventricle is in the passive filling phase.
To learn more about ventricle here
https://brainly.com/question/4405104
#SPJ4