Christopher Reeve became paralyzed from the neck down after a severe horse- riding accident on May 27, 1995, during an equestrian competition in Culpeper, Virginia. He was thrown headfirst from his horse and landed on a jumping rail, which shattered his first and second cervical vertebrae (C1 and C2) and severely damaged his spinal cord

. The injury left him unable to move or feel anything below the neck and unable to breathe without a ventilator, as the damage was at a very high level in the spinal cord. He was initially classified as having a complete spinal cord injury (ASIA Grade A), meaning no motor or sensory function below the shoulders

. Reeve underwent surgery to stabilize his neck and spinal column, followed by extensive rehabilitation. Despite the initial prognosis that recovery was impossible, he eventually regained some small movements and sensations through intense physical therapy

. In summary, Christopher Reeve's paralysis was caused by a traumatic spinal cord injury resulting from the impact of falling and landing on his neck during a horse-riding accident, which fractured the top two vertebrae and damaged his spinal cord at the C1-C2 level