Pinned vertebrae. Coloured X-ray of pins (beige) joining two of the vertebrae (pink) of a 29 year old woman together to immobilise them. Vertebrae are the box-like bones that make up the spine. They protect the spinal cord and support the body. Normally, vertebrae are separated by intervertebral discs, flexible pads that impart a degree of flexibility to the spine and help it to absorb shocks. However, the disc between the two pinned vertebrae was damaged, and the two were joined together to prevent further damage occurring. The two pinned vertebrae are L3 and L4, in the lower (lumbar) back. The pelvis is seen at bottom, with some ribs at upper left and right.