Vertebrae. Model of three vertebrae from the human spine. The vertebrae are separated by intervertebral discs (grey). Vertebrae are bones with a wide, disc-like body and bony processes projecting out from the rear (left). These processes are the attachment points of muscles. The intervertebral discs cushion the bones from one another, acting as a kind of shock absorber and allowing the spine a degree of flexibility. The spinal cord runs down through gaps in the bony processes immediately behind the body of the vertebrae. The spine is made up of 33 vertebrae, which vary in shape depending on their position, but all have the same basic structure.