It is well known that the spinal cord travels within the spinal canal and therefore the spinal column functions to protect the spinal cord. The spine consists of 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, a sacrum (formed by the fusion of 5 sacral vertebrae) and a coccyx. The vertebral segments are connected to each other by intervertebral discs. The intervertebral disc consists of a jelly-like nucleus pulposus in the middle and a surrounding fibrous ring. The discs, the bony structures of the vertebral segments, ligamentous tissues and muscles together form the stable structure of the spine. In the fetus, the length of the spinal cord differs very little from that of the spinal canal. However, due to the different growth rates of the spinal column and the spinal cord, in adulthood, the spinal cord and the spinal column are of unequal length, with the spinal cord being shorter than the spinal column. Therefore, after the spinal nerves in the lumbosacral region are separated from the spinal cord, they must travel some distance down the spinal canal before extending from the corresponding intervertebral foramen. The spinal cord includes conduction tracts that run up to and from the brain, innervating the movement and sensation of the extremities and trunk. Nerve roots emanate from the spinal cord and conduct nerve signals from the spinal cord to the muscles and sensory formation to the spinal cord. When a traumatic injury to the spine produces paraplegia or incomplete paralysis, it is important to be clear about their interrelationship in order to determine the exact site of the injured spinal cord. For example, after an injury to the 10th thoracic vertebra due to a car accident, the 10th thoracic medullary segment is not injured, but the 12th thoracic medullary segment. Therefore, it is important to understand the true anatomical relationship between the spinal cord and the spine in order to determine the true plane and extent of the patient’s injury, so that proper treatment can be administered.