This image shows a magnified view of the anterior (ventral) half of the spinal cord.  Along the anterior median line of the spinal cord is a fissure called the anterior (ventral) median fissure.  In the gray matter on the median lines lies a small central canal.  This canal (filled with cerebrospinal fluid) runs the length of the spinal cord and is continuous with the ventricles of the brain.   Notice that the gray matter is organized into anterior (ventral) horns, which contain the nerve cell bodies of the motor neurons that innervate skeletal muscle.  The gray matter on each half of the spinal cord is joined together by the gray commissure,  which contains the central canal.  On each side of the spinal cord,  the anterior  horns of gray matter divide the white matter into columns called the anterior and lateral funiculi.  These columns contain tracts made up of nerve fibers (axons) that carry action potentials to and from the brain and to other levels of the spinal cord.