Each year, there are approximately 12,000 spinal cord injuries (SCI) in the United States. These devastating injuries occur occur when severe trauma to the spine fractures or dislocates vertebrae, causing the spinal cord to bruise or tear. Spinal cord injuries exhibit a broad range of severity ranging from incomplete to complete. In incomplete SCI, sensation and movement is partially lost below the site of injury. In complete SCI, all sensory and motor functions below the site of injury are completely and permanently lost, resulting in paralysis. The riding accident that resulted in the paralysis of Christopher Reeve is an example of a complete SCI. The location of the SCI also determines the extent of injury. Injuries in the thoracic or lumbar regions can affect the torso, legs, bowel and bladder control, and sexual function. If the injury occurs in the cervical region, the ability to speak, breathe, and use arms can also be impaired. Although there are several treatments available for SCI victims, the damage from injury is largely irreversible.