Surfer's myelopathy is a rare nontraumatic paraparesis/paraplegia. It is a spinal cordinjury caused by hyperextension of the back. When the back is hyperextended, a blood vessel leading to the spine can become kinked, depriving the spinal cord of oxygen. For this reason, it is sometimes referred to as "a stroke of the spinal cord." The condition gets its name because the phenomenon is most often seen in those surfing for the first time, but it can be caused by any activity in which the back is hyperextended (yoga, pilates, etc). The majority of patients suffering from surfer's myelopathy have a complete or near-complete recovery, but in some cases the paralysis is permanent. As of 2007 there were 9 recorded cases but the number of people actually afflicted is higher.