one of several interacting cavities in the brain. There are four ventricles: two lateral ventricles, the third ventricle, together with 4th ventricle. The lateral ventricles come in the cerebral hemispheres. Each horizontal ventricle contains a triangular central human anatomy and four horns. The horizontal ventricles keep in touch with the 3rd ventricle through the interventricular foramen (orifice). The third ventricle is a median (midline) cavity inside brain, bounded by the thalamus and hypothalamus on either part. Right in front, the third ventricle communicates using horizontal ventricles, as well as in back it communicates using aqueduct associated with the midbrain (the aqueduct of Sylvius). The 4th ventricle is considered the most substandard associated with four ventricles regarding the brain. It expands through the aqueduct regarding the midbrain into central channel of higher end of the spinal-cord, with which it communicates because of the two foramina (spaces) of Luschka and foramen of Magendie. The ventricles tend to be filled with cerebrospinal fluid, that is formed by frameworks, called choroid plexuses, which are located in the walls and roofs regarding the ventricles.