Structure  - slit like space  - Lined by ependymal cells   Walls of third ventricle Anterior = Anterior column of fornix, Anterior Commissure and Lamina terminalis Posterior = Pineal body, Posterior commissure, Commencement of Cerebral aqueduct Roof = Ependyma connecting two thalami Floor = Optic chiasm, Infundibulum of pituitary, mamillary body, posterior perforated substance, Tegmentum of midbrain Latera wall = Thalamus, hypothalamic sulcus   Foramina of third ventricle 1. 2x Foramen of Monroe (connects thrid ventricle to lateral ventricles) 2. Cerebral aqeduct (Sylvian aqueduct) - connects third ventricle to fourth ventricle   Recesses of third ventricle 1. Infundibular recess 2. Optic recess (chiasmatic recess) 3. Anterior recess (vulva of third ventricle) 4. Supra pineal recess 5. Pineal recess   Other Structures of Thrid ventricle  - interthalamic adhesion  -  hypothalamic sulcus  - Choroid plexus - lies in roof and hangs from the tela chorodea