Chiropractic was started by D.D. Palmer (left) near the turn of the century and developed by his son B.J. Palmer. Palmer was a spiritualist who thought that misalignments in the spine blocked the life force from the brain to the rest of the body.
Chiropractic followed the route of the typical placebo effect. It started by focusing only on the upper cervical vertebrae. Initially, like most new placebo therapies, people claimed dramatic miraculous results. Then, like most placebo therapies, the results began to wane and the technique was tampered with again and again. Each time some change was made to the upper cervical adjustment, results improved and then waned as it became old again and the hope and expectation that drives the placebo effect diminishes. This went on and on until the placebo effect waned to the point where people decided to start tampering with the whole axial skeleton from occiput to coccyx. The idea was to restore the flow of the nerve impulse from brain to body by removing vertebral subluxations (tiny misalignments of the vertebra). Up until this point, there wasn't a word about neck or back pain. It never originally had anything to do with neck or back pain.
But by the 1950's, Chiropractors noticed that there was an effect on pain from adjusting the spine. The original placebo miracles of D.D. Palmer's adjustments were too rare now to provide effective marketing, so there was a campaign to start selling the profession based on musculoskeletal pain relief. Since then, there has been enormous confusion between the metaphysical/life force/placebo effects of Chiropractic and the musculoskeletal therapeutic effects of the adjustment.
Many Chiropractors want to focus on the metaphysical aspects of original Chiropractic while many see the metaphysical ideas of original Chiropractic as bunko and want to focus on pain relief. Most combine the two ideas and hope to draw as many patients as possible into their net.
Insurance companies hate Chiropractors. When Chiropractors bill for insurance, they mark subluxation codes no matter what the patient is coming for and no matter what the Chiropractor is doing. There is not the slightest bit of reliable evidence that tiny subluxations have any effect at all on anyone. As most of my practicing Chiropractic friends have told me personally, "I don't give a shit about sublxations". Old time Chiropractors who have been getting regular adjustments to fix "subluxations" for most of their lives are currently dropping off like flies, dying before their time.