A section through a mouse vertebra at 200x magnification
The vertebrae that make up our spine have the critical task of housing and protecting the spinal cord, a thin bundle of nervous tissue hooked up directly to the brain. The spinal cord in part transmits movement information from the brain to the muscles. In fact, the function of the spinal cord can be divided into segments based on the muscles they control: Nerves from the lower vertebrae in the neck help extend the elbows and flex the wrists, while nerves from the lower back vertebrae assist in extending the legs and toes. Spinal cord injury can result in different degrees of paralysis depending on which segment was affected.
Image by Dr. Michael Nelson and Samantha Smith, University of Alabama at Birmingham.