This image is a graphic depiction of how nerves from the spine go to the various organs in the human body. Versions of it can be found on the walls of thousands of chiropractic offices. Some have been turned into light boxes that illuminate certain organs when specific vertebrae are touched. Chiropractors use the chart to explain how subluxations, small misalignments of vertebrae believed to interfere with normal nerve function, can lead to dis-ease, dysfunction, and eventually disease in any part of the body. Worse yet, subluxations often don't announce themselves. They are the SILENT KILLER - only your chiropractor knows they are there, and only your chiropractor can fix them.
What a good deal for your chiropractor! If there was evidence that subluxations were responsible for ill health, and correcting them assured a long and healthy life, we'd all line up around the block to see our local chiropractor, myself included! Chiropractic care would empty the hospitals, as Dr. Sid would say (see this post), drug companies would go bankrupt, everyone's health insurance would cover 100% of the cost of chiropractic care, and insurance premiums would be a small fraction of their current cost.
Subluxations are more than a cunning ploy to sucker people into chiropractic offices and keep them coming back. Most chiropractors firmly believe in the existence of subluxations (see the data in part 1 of this series), and many of those docs are as passionate as evangelists in their insistence that becoming and staying subluxation-free will improve a person's physical, mental, and spiritual well-being.
A Google search for the term subluxation results in over 12 million returns. Many of those websites belong to chiropractors, and they inform us of the evils of vertebral subluxations and the benefits to be had from lifelong chiropractic care. A search for "subluxation silent killer" produces nearly 1.7 million returns. Moving past the first several sites, which will inform you that there is no scientific evidence for these gremlins of the backbone, you'll find plenty of websites from chiropractors eager to recruit you into the army of the well-adjusted. Click on any one of these links and you're likely to summon a fervent argument for getting your spine checked for subluxations.
But where's the evidence? Chiropractors often refer to a study published in The Medical Times of November 1921 (yes, 1921, not 2021) by a medical doctor, Henry Winsor, titled Sympathetic Segmental Disturbances-II: The Evidence of the Association, in Dissected Cadavers, of Visceral Disease with Vertebral Deformities of the Spine of the Same Sympathetic Segments.  Winsor examined 50 cadavers, compared the diseased organs he found with "curvatures" of the cadavers' spines, and determined there was a high correlation between the diseased organs and the distribution of the sympathetic nerves from the vertebral levels of the curvatures.
"221 structures other than the spine were found diseased. Of these, 212 were observed to belong to the same sympathetic segment as the vertebrae in curvature."
Correlation does not prove causation, but many chiropractors see this hundred year-old study as proof that bony misalignments of the spine cause disease in the organs supplied by spinal nerves emanating from the subluxated segments. (See this post on the website Science-Based Medicine for a catalog of flaws inherent in Dr. Winsor's methodology.)
Also compelling to subluxation-based chiropractors is the oft-cited statistics on Spanish flu cases treated by chiropractors versus those treated by medical doctors. This information experienced a resurgence during the COVID pandemic amidst chiropractic claims that spinal adjustments improve immunity.  As far as I can determine, the only source of the information is Dr. Walter Rhodes, a Texas chiropractor, who wrote The Official History of Chiropractic in Texas . Excerpts from the book were widely disseminated by the wildly popular Dan Murphy, DC.  Here are some of the statistics as reported by Dr. Rhodes.
In Iowa, including the city of Davenport, home of the Palmer School of Chiropractic, chiropractors and chiropractic students treated 6,370 cases of Spanish flu with only 7 deaths or one death for every 910 patients treated. The death rate of patients under medical care was one out of 15.
Nationally, in the year 1918, 46,394 patients with Spanish flu were treated by chiropractic with a loss of 54 patients, which is one out of 859 people. (Rhodes states it was one out of 886 patients.)
In New York City in 1918, "drugless methods"(apparently not limited to chiropractic treatment although Murphy states chiropractic care "is assumed") accounted for 399 successes for every 400 patients, i.e., 25 deaths out of 10,000 patients. Medically treated patients died at a rate of one out of 10.5. (Osteopaths have made their own claims of success in the treatment of Spanish flu patients, claims that are not scientifically valid but at least somewhat more plausible than the chiropractic ones. This topic is addressed in my forthcoming book.)
Oklahoma claimed 7 deaths out of 3,490 patients treated with chiropractic, a rate of just under one out of every 500 patients. Rhodes also reported on a subset of Oklahoma patients. Of 233 influenza cases given up as lost by MDs, all but 25 were saved by chiropractic treatment.
"Chiropractors got fantastic results from influenza patients while those under medical care died like flies all around," wrote Rhodes. If these statistics were true, then chiropractic should be the first line of treatment for influenza and its common complications such as pneumonia. Indeed, many chiropractors favor this approach. However, above and beyond these astonishing statistics, it is amazing that so many chiropractors are eager to believe that spinal adjustments - excuse me, the correction of vertebral subluxations - prevented thousands of deaths during the Spanish flu pandemic.
"The weight of evidence for an extraordinary claim must be proportioned to its strangeness," said the early nineteenth century scientist Pierre-Simon Laplace, which Carl Sagan popularized as "Extraordinary claims require extraordinary evidence." Unfortunately, the evidence for these extraordinary chiropractic claims is far from exceptional. In addition to "several thousand letters, articles, periodicals and notes …" and tape recorded interviews with 35 individuals, Rhodes lists 28 specific sources in his book. However, these sources are not referenced in the text itself, so it is not possible to determine which ones are for the claims of chiropractic successes in treating people with the Spanish flu. Furthermore, none appear to be the type of research study that might lend veracity to these claims.
But Dr. Rhodes himself should not be blamed for the lack of scientific accuracy in collecting and reporting this information. Scientific methods of data collection and interpretation a century ago are no match for the highly sophisticated and computerized techniques available today. Nonetheless, I find it appalling that so many chiropractors are so willing to believe even the weakest crumbs of data as proof of what remains an unsubstantiated hypothesis. Even if reliable data were sourced, which is highly unlikely given the times in which the data were collected, the information can provide nothing more than a topic for basic science and clinical research to determine the veracity and efficacy of this therapeutic intervention. And in the century between the Spanish flu and the current COVID pandemic, chiropractors have done virtually no scientifically-valid research into the potential mechanisms by which adjustments allowed those stricken with the flu to survive.
In the absence of scientific evidence, chiropractors are marching in the parade to promote chiropractic on the basis of one man's claims, those of Dr. Walter Rhodes, backed by the fiat of authority granted to people like Dr. Dan Murphy, and driven by the engine of confirmation bias, i.e., the tendency to believe information that is consistent with beliefs already strongly held. One explanation for the apparent improvement made by patients receiving chiropractic treatment for the Spanish flu is that some patients returned to normal health following the initial onset of symptoms, only to experience an aggressive return of the disease followed by death. Conceivably, if those patients had received chiropractic care, their remissions might be chalked up as a cure. Another possibility is that some of those patients did not actually have influenza of the Spanish variety (Spanish flu is itself a gross misnomer; see Fun With Spanish Flu Myths) but some type of self-limiting infection.
I'm not trying to take the role of a party pooper here. My purpose is to suggest plausible reasons for not accepting these extraordinary claims as factual and thus as proof for the subluxation hypothesis. "The aim of science is not to open the door to infinite wisdom, but to set a limit to infinite error," Bertolt Brecht wrote. When I searched for information to write this post, I came upon the claims of other healthcare professions, homeopaths and osteopaths, regarding their successes in treating patients with the Spanish flu. The ones by osteopaths are particularly interesting because their treatment methods are thought to parallel those of chiropractors although many of the osteopathic techniques reportedly used to treat Spanish flu are quite different than chiropractic spinal adjustments.  Their claims have a modicum of support from plausible explanations, and some osteopaths have pursued research to determine mechanisms by which their manipulations could help patients fight disease. 
Chiropractors who are zealots of subluxation ideology have their own journals and websites. Their views are often extreme, and they vehemently oppose opinions contrary to their own. In the next installment of this series on the subluxation hypothesis, The Silent Killer - epilogue, I present a recent email discussion with one of the foremost proponents of the subluxation ideology and conclude with a review of Dr. Joseph Keating's classic article, Subluxation: Dogma or Science?
Sixteen researchers, including some who are internationally recognized, collected examples of misinformation about chiropractic treatment and its ability to prevent or impact COVID-19 from the internet and social media. They stated, "These beliefs often stem from nineteenth-century chiropractic concepts. We are aware of no clinically relevant scientific evidence to support such statements." Axén I, Bergström C, Bronson M, Côté P, Nim CG, Goncalves G, et al. Misinformation, chiropractic, and the COVID-19 pandemic. Chiropr Man Therap [Internet]. 2020 Nov 18 [cited 2022 Apr 10];28:65. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7672412/ back
Rhodes WR. The Official History of Chiropractic in Texas. Austin, Texas: Texas Chiropractic Association; 1978. I am grateful for the help of Jennifer Smith at the David D. Palmer Health Sciences Library at Palmer Chiropractic College, Davenport, Iowa for her help in obtaining this material. back
The osteopathic techniques reportedly used to treat Spanish flu are quite different than chiropractic spinal adjustments. See Osteopathic manipulative treatment and the Spanish flu: a historical literature review. back
Hruby RJ, Hoffman KN. Avian influenza: an osteopathic component to treatment. Osteopath Med Prim Care. 2007 Jul 9;1:10. back