Kidneys and lumbar spinal cord. Coloured coronal magnetic resonance imaging (MRI) scan of the lower (lumbar) spine of a 28-year-old woman, also shown the kidneys (pink). The scan shows the spinal cord enclosed by the vertebrae of the backbone. At this level (the L1 to L3 vertebrae), the spinal cord forms a bundle of branching spinal nerves and nerve roots known as the cauda equina (centre).