There was an interesting story last week about a man breaking his neck on a roller coaster. If you read the accompanying article http://www.mirror.co.uk/news/uk-news/man-breaks-neck-freak-accident-4524404 it says he has spondylitis. That just means inflammation of the vertebra but my suspicion is that it is ankylosing spondylitis (AS). The photo of him makes him look quite scary but I think he looks like that because he is having to lookup at the camera with his eyes because his upper back is fixed in a classic AS question mark shape. In AS inflammation of the vertebrae can cause microfractures and the discs to wedge, leading to a pronounced curvature, the ligaments and discs between the vertebrae then ossify preventing the patient from being able to straighten that curvature to lookup at the camera. It also means that the back acts as one long (curved) pole like lever, so when his head snaps back on the rollercoaster, with a relatively small force, all of that energy is concentrated on the first bit that moves, which also coincides with where the curves in the spine change direction. That is why I suspect he has had a fracture at C5-6 or C6-7 and that explains why he went limp but didn't die. Injuring the spinal cord at that level will cause spinal shock leading to floppy paralysis below that level; however the nerve supply to the diaphragm leaves the spinal cord above these levels and travels down separately so he will still be able to breathe.
Damian is the principal osteopath at Vauxhall Village Osteopathy and Oval Osteopathy