The level of injury, also known as a lesion, is the point in the spinal cord where the damage has occurred. This can be determined by counting the nerves from the top of the spine downwards. These nerves are grouped into four areas: the Cervical, Thoracic, Lumbar, and Sacral, i.e. the four sections of the spine. Damage to the spinal cord at these points determines how muscles, organs, and sensations will be affected. There are also two types of lesions: complete injury and an incomplete injury. A complete injury will cause a complete loss of muscle control and sensation below the level of the lesion. An incomplete injury will cause paralysis in only the muscles directly affected or impaired sensation. Identifying the level and type of lesion is important in determining the severity of the paralysis.