The<unk>  is the terminal end of the spinal cord. It occurs near lumbar nerves 1 (L1) and 2  (L2). After the spinal cord terminates, the spinal nerves continue as dangling nerves called the cauda equina. The upper end of the<unk>  is usually not well defined.
Conus medullaris
Plexus
Trigeminal motor nucleus
Trigeminal nerve nuclei
Ganglion
Tectospinal tract
Dendritic spine
Bulbus cordis