I would say this looks like MBD in lizards, but I don't know how a snake would get it because they get the proper ratio of calcium to phosphorous in their feeders unless your feeders were seriously un-healthy...but really, that is what it looks like, or a kink of some type.
But snakes can and do develop diseases and genetic things that make them get like this as they age. One thing called Osteitis Deformans causes things that look like this, like bone swellings or an area where the spine is deviated.