The spinal cord is considerably shorter than the spinal canal itself. The nerve roots angle downward increasingly from top to bottom from where they exit to the spinal cord to where they exit from the canal. The spinal canal below the level of L1 contains no spinal cord, only nerve roots. Bundled together the nerve roots resemble the strands of a horse's tail and are referred to collectively as the cauda equina (Latin term meaning horse's tail).