When both legs and arms are affected, the condition is called Quadriplegia. Paraplegia is usually the result of Spinal Cord Injury (SCI) or a congenital condition such as Spina Bifida which affects the neural elements of the spinal canal.The area of the spinal canal which is affected in paraplegia is either the thoracic, lumbar, or sacral regions.he human spinal cord consists of nerves that connect the brain to nerves in the body. It is a superhighway for messages between the brain and the rest of the body. What is Quadriplegia and Paraplegia. Definition of Quadriplegia and Paraplegia including interesting spinal cord injury (SCI) statistics.