Chiropractic was founded in 1895 by D.D. Palmer on the theory that vertebral subluxations — minor misalignments of spinal bones — compress nerves and interrupt "innate intelligence" flowing through the body, causing systemic disease. Correcting these subluxations through spinal manipulation was proposed as treatment not just for back pain, but for asthma, ear infections, infant colic, autism, cancer, fibromyalgia, and organ dysfunction. The International Chiropractors Association still holds that "the concept of subluxation is essential to chiropractic, just like oral health is essential to dentistry."

Proponents have spent over a century attempting to establish that spinal misalignments produce measurable nerve interference, that nerve interference produces organic disease, and that manual correction reliably reverses disease. They hoped X-ray analysis would provide objective evidence of subluxation location and severity. They hoped patient outcomes would demonstrate efficacy beyond musculoskeletal complaints. Neither has been established to scientific standards.

• The chiropractic subluxation as defined has never been demonstrated to exist as a distinct pathological entity
• Even severe nerve root compression — a real, measurable phenomenon — does not cause the systemic organic disease subluxation theory predicts
• X-ray measurements of spinal alignment vary significantly based on patient positioning, time of day, hydration, and emotional state — making them unreliable diagnostic tools for subtle misalignment
• Systematic reviews find no conclusive evidence for chiropractic treating asthma, colic, autism, fibromyalgia, gastrointestinal problems, or carpal tunnel syndrome
• For low back pain, effect sizes are below the threshold for clinical significance in multiple studies
• Two thirds of chiropractors disciplined by state boards are sanctioned for fraud and sexual boundary violations — not negligence — suggesting a systemic culture problem beyond clinical error

• The profession is internally divided. A significant minority of chiropractors explicitly reject subluxation theory and practice evidence-based manual therapy for musculoskeletal conditions only. Painting all chiropractors as fraudulent misses this.
• Spinal manipulation is not unique to chiropractic. Physical therapists and osteopaths perform similar manual techniques with a stronger evidence base and without the subluxation framework.
• Adverse event rates are likely underreported. The profession's own malpractice insurers decline to release data, making stroke and injury incidence estimates unreliable in both directions.
• Insurance coverage creates perverse incentives. Medicare and many insurers pay for chiropractic, creating financial pressure toward overtreatment regardless of clinical justification.
• The placebo effect is real and valuable. Some patients experience genuine pain relief from chiropractic, likely mediated by touch, attention, and expectation — not subluxation correction. This does not validate the theory but matters for patient experience.
• Regulation varies wildly by state. Some states require chiropractors to carry malpractice insurance; most do not. Some require informed consent for cervical manipulation; many do not.