Hunters ridge

Question
hello, my age is 42; i would say intermediate horse experience. but still learning.
my sister and I have just adopted/rescued a 17 yo, twh, mare.  very sweet, but she has what i'm told to be hunters ridge. half way down the back to the rump is elevated vs. swayed
we have not ridden her at this time, we perfer to give her a little time to adjust first.
Do you have any knowledge about this?  i am working on getting the pictures.  

I appreciate your assistance.

Answer
I think this is also called a hunters bump.  There is a lot of different beliefs about this, I hear that it can be caused from jumping too much, too high or when a horse slips or falls and does the splits with his back legs.  Some people swear by a horse chiropractor to pop it back in, check with a couple of vets and get advice to make sure it is not a slipped disk or spinal issues, but, I know horses that get it popped back in and are fine.  Be aware that it may be painful to the horse which may cause him to buck or get fearful from the pain and run off or roll over or flip back, so be careful.