"The spinal cord is like the brain's tail, as it winds its way through the spinal canal, formed by the stacking of the donut-shaped holes in each bone (vertebra) of the spine. Like an upside down tree, with the root as the brain and the spinal cord as the trunk, the branches are formed by the 31 pairs of nerves exiting the spine. These branches exit the spinal canal through holes (intervertebral foramen), just in front of the joints (called pedicles) that limit our rotation, preventing the 180 degree rotation as was shown in the neck during the Exorcist movie."