I find it incredible that there is a completely independent field of "healing" that cannot produce one study verifying that their methods work better than tradition medicine, or even no treatment at all, and that this field cannot adequately define or describe the basic pathology they treat or the treatment for it.
"Chiropractic" is a example of a closed, self-referential system. As such, it is not susceptible to disproof, which means it fails the cardinal test of what it takes to be considered a "scientific" theory.
Chiropractic "theory" hypothesizes the existence of disturbances in mysterious (and undetectable) "energy flows" in the body and then relies upon skeletal "manipulations" to restore the proper balance in the "energy flows." But this is intellectually equivalent to hypothesizing that when you feel bad, it is because of invisible (and undetectable) gremlins inside your head, but after massaging your head with magnetic gloves for an hour (at $250/hr)) I can make the invisible gremlins go away. At the end of the hour, I say "They're all gone! Feel better?" And of course you'll say "Yes!" (An hour of massage will make anybody feel better, unless they are profoundly ill.) I'll be $250 richer, you'll be $250 poorer, but you'll "feel better" especially knowing that the invisble gremlins are gone from your head.
That's not practicing medicine.... it's practicing witchcraft -- and fraud.