The back bone is fine, it sets down between the muscle, not "Jumper's Bump". It's the muscle that seems to be developed at the top, then not down to the tail dock. Or maybe it's a fatty deposit and not muscle? The horse has had not work for at least a year. I'm thinking about getting the horse, but would be interested to know if this indicates an injury or is just poor condition. Thanks, will try to get a picture.