Ventricles of the brain are cavities that are located within the cerebral hemispheres along with the brain stem.  These spaces are connected with the central canal of the spinal column and, like the spinal column, are filled with cerebrospinal fluid.  The ventricles that are the largest consist of the 1^st and 2^nd or lateral ventricles that spread out into the cerebral hemispheres and inhabit parts of the frontal, occipital and temporal lobes.  The 3^rd ventricle is situated in a space that is narrow and located in the midline of the brain.  This 3^rd ventricle joins the lateral ventricles thru an opening in the front of it, called the “interventricular foramina”.  The 4^th ventricle is situated in the stem of the brain, right to the front of the cerebellum.  A slender canal referred to as the “cerebral aqueduct” joins this 4^th ventricle to the 3^rd ventricle. This canal also passes length wide thru the stem of brain.  This ventricle is touching the central canal of the spinal cord and in the roof has openings that go into the meninges which are the membranes covering the brain and spinal cord.