The hierarchy of practitioners who fix mechanical problems with the body (sprains, tears, dislocations, etc etc) goes something like this:
PHYSIOTHERAPIST: extensive theoretical and practical training at academic institutions, internationally-recognised certifications. Think of these people as the engineers of the body. They've studied how shit works, they've tested how shit works, and they know why shit happens. The solutions offered by physiotherapists are often hard work, and involve a lot of pain. And the physios don't care. If you're too lazy to do the weeks of painful exercises that will repair your body, it's your own fucking problem.
CHIROPRACTOR: not-so-extensive theoretical and practical training at schools which may or may not be officially recognised, certifications vary from country to country. Think of these people as hobbyists of the body. They don't have the formal background and rigorous testing of the engineers, but they have a pretty good amateur understanding of how shit works. If an engineer designs and tests engines in a laboratory, the hobbyist is good at tweaking his own car for performance in his garage at home. As Pimp-X said above, often chiropractors focus on making the patient feel better rather than fixing the problem.
Physiotherapists and chiropractors sometimes move in the same circles and belong to the same organisations (e.g., the NZ Manipulative Therapists Association), in the same way that you might often see formally-qualified professional computer scientists and bedroom hackers together at a Linux conference.
OSTEOPATH: no required theoretical or practical training. Basically... quacks. This is the "magnets, reflexology, your-pain-is-caused-by-repressed-memories-of-Satanic-abuse" shallow end of the pool. If physiotherapists are engineers, and chiropractors are knowledgable amateurs, then osteopaths are... well, if an engineer designs and tests engines in a laboratory, and the hobbyist is good at tweaking his own car for performance, then the osteopath knows that putting on a bigger exhaust, a spoiler, and lowering the car makes it GO FASTERER!!!1. In the same way that idiot riceboys sometimes do things that actually DO improve performance, the osteopath can sometimes do things that actually DO make the patient feel better. They just don't really know why. The solutions offered by osteopaths usually involve an impressive noise (i.e., they know that if you jerk someone upright, their spine might go "crack") and short-term pain relief. If you start hurting again the moment you walk out the door, the osteopath doesn't know why, but he already has your money... so make another appointment to hear the cool cracking noise! And you felt better immediately! For ten whole minutes! And you didn't have to do ANY work!
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