Third ventricle

The third ventricle is bound by the two thalami anterolaterally and the hypothalamus posterolaterally. At the anterior end lies the lamina terminalis, columns of the fornix, and anterior commissure. The pineal gland, habenular and posterior commissures are located at the posterior end. The choroidal fissures and bodies of the fornix lie above. Like the lateral and fourth ventricles, the third ventricle contains a choroid plexus, which produces cerebrospinal fluid. It also communicates with the lateral ventricles via the foramina of Monro and the fourth ventricle via the aqueduct of Sylvius.