The sensory and motor level need to be evaluated for both the right and left sides of the body. It is not unusual to have a discrepancy between the lowest normal motor level and the lowest normal sensory level. The physician uses this evaluation to classify the injury as complete or incomplete and assign a level of injury. Another way that the level of spinal cord injury can be categorized is tetraplegia and paraplegia. Tetraplegia, previously called quadriplegia, refers to injuries of the cervical region of the spinal cord.
Paraplegia refers to injuries which occur in the thoracic, lumbar, or sacral segments.
When a spinal cord injury is graded as incomplete, it means the cord has been partially damaged. A complete injury indicates a complete blockage of nerve messages. With a complete injury there is no sensation or motor function in the lowest sacral segment. The nerve rootlets leave the spinal cord continually and then aggregate into nerve roots. In a spinal cord injury, only fractions of the rootlets going to a nerve root level may be damaged.