Lumbar vertebrae, side (lateral) view. This computer artwork shows two lumbar vertebrae (pink) in the lower part of the spine. The back of the spine is on the left, where the bony projections or processes can be seen; these are where muscles and ligaments of the back attach to the spine. Intervertebral discs (brown) form joints between the vertebrae, allowing for slight movement and cushioning against impact. These consist of an outer layer of fibrous and cartilaginous tissue and a jelly-like centre.