Spinal anatomy. Labelled diagram of the anatomy of the spinal (vertebral) column. The vertebrae are numbered according to the region (shown at centre): cervical (pink, neck, C1-C8), thoracic (purple, upper back, T1-T12), lumbar (blue, lower back, L1-L5), and the fused vertebrae of the sacrum (green) and coccyx (orange) at the base of the spine. The anatomical areas labelled at top and down left are: the skull, the spinal cord, the vertebral bodies, the intervertebral discs, the dura mater (thecal sac, membrane surrounding the spinal cord), the spinous processes, the conus medullaris, and the cauda equina. The conus medullaris is the tapered, lower end of the spinal cord, The cauda equina is a large bundle of spinal nerves branching from the end of the spinal cord.