Injuries to the spine are not regarded in the same category as a general back injury. Back injuries often occur due to nerves that are pinched or disks that rupture after trauma or an overload of stress. Many people suffer from a back injury and do not damage their spinal cord, even if they break a vertebra in an accident.
Specifically, spinal cord injuries are classified as when there’s a lack of mobility or feeling. In a complete injury, a person would not have any sort of feeling or function in the area below the injury. Doctors regard incomplete spinal cord injuries as instances where a person does have some sort of sensation or motor ability in the areas below the actual injury.