Mine can lay me on my stomach, ask me to move my arms in various regular movements, and from the moves watch my legs shift shorter or longer. Based on that, he knows which vertebrae are out of alignment.
I have tested him on several occasions with ailments related to possible nerve pinching. He has been flawless at telling me what the problem was without me giving the slightest indication of symptom (sometimes it'll be heartburn, sometimes headache, or some other area of the body.). He's incredible, really. The body is, after all, just a collection of parts controlled by a central nervous system that runs through the spine.
Learn the central nervous system (spine) and you can do a lot to affect the overall condition of the body. Would we respect an auto mechanic who refused to look at the engine when the car didn't start?
Anthony
You can lead a horse to water but you can't make him think.