When I graduated from Lincoln Chiropractic College in 1956, I had come to the conclusion that chiropractic’s subluxation theory, that misaligned vertebrae can cause organic disease, was not true. When I began my practice in Panama City, Florida, I limited my practice to care of mechanical-type back pain and related problems. Back then, that was not too much of a stretch, since manipulative services were not readily available in medical practices and there were a number of orthopedic and physical medicine texts recommending use of manipulation in the treatment of back pain.

In 1963, I published my book Bonesetting, Chiropractic, and Cultism, renouncing subluxation theory and recommending that chiropractic be developed as physical treatment specialty in the care of back pain. The book was reviewed by the Library Journal (February 1, 1964) and recommended for inclusion in medical and reference libraries. In 1965, I received a letter from the American Chiropractic Association (ACA) informing me that my application for membership in the ACA had been rejected. In the years to follow, I published many articles in an attempt to initiate an effort to change chiropractic from a subluxation-based practice to a legitimate physical treatment method that would fit in with mainstream health care. My suggestions were ignored and I was called a “chiropractic heretic.” Today, I find myself still saying some of the things I said in my 1963 Bonesetting book, still being rejected by most of my colleagues and still voicing opposition to subluxation theory.

There are now some chiropractors who do not subscribe to the theory that some kind of segmental dysfunction in the spine can cause organic disease, but they are overshadowed by subluxation-based chiropractors who publish their own journals, using scientific-sounding jargon to defend implausible theories and dubious treatment methods. Some of these chiropractors do not use the “subluxation” word, instead substituting some other vague description of a spinal lesion, such as “joint dysfunction,” alleged to have the same affect on the nervous system and general health as a “vertebral subluxation.”

The status of chiropractic vertebral subluxation

In the United States, state laws and chiropractic publications define chiropractic as a method of correcting vertebral subluxations to restore and maintain health. A 2010 publication of the National Board of Chiropractic Examiners (NBCE), Practice Analysis of Chiropractic, states that “The specific focus of chiropractic practice is known as the chiropractic subluxation or joint dysfunction. A subluxation is a health concern that manifests in the skeletal joints, and, through complex anatomical and physiologic relationships, affects the nervous system and may lead to reduced function, disability, or illness.” This definition of chiropractic is in keeping with a paradigm formulated by the Association of Chiropractic Colleges (ACC) in 1996, signed by 16 North American chiropractic college presidents: “Chiropractic is concerned with the preservation and restoration of health, and focuses particular attention on the subluxation.”

When the Council on Chiropractic Education (CCE) published its proposed 2012 Accreditation Standards for chiropractic colleges, reference to the word “subluxation” was omitted. The American Chiropractic Association (ACA) responded, in part, arguing that “The elimination of any reference to this term in the proposed standards will be viewed by many within the profession as a counter productive action that will, in the long-term, likely weaken the profession’s collaborative strength and historical identity.“ The CCE compromised by using the nebulous phrase “subluxation/neuro-biomechanical dysfunction” in the final 2012 Standards in order to satisfy advocates of the vertebral subluxation theory. (An open letter to the profession from CCE, Nov 22-11) Obviously, the factory of the chiropractic profession has not discarded subluxation theory. Chiropractic associations continue to reflect the views of the majority, even if such views are based on a belief system.

At least one recent study by individual academic chiropractors has concluded that “No supportive evidence is found for the chiropractic subluxation being associated with any disease process or of creating suboptimal health conditions requiring intervention.” (Mirtz, et al. An epidemiological examination of the subluxation construct using Hill’s criteria of causation. Chiropractic and Manual Therapies. 2009;17:13)

Another independent study by academic chiropractors revealed that “Despite the controversies and paucity of evidence the term subluxation is still found often within the chiropractic curricula of most North American chiropractic programs.” (Mirtz & Perle. The prevalence of the term subluxation in North American English-Language Doctor of Chiropractic programs. Chiropractic and Manual Therapies. 2011;19:14)

It will not be enough for chiropractors and chiropractic colleges to substitute such words and phrases as “joint dysfunction,” “vertebral subluxation complex,” and “subluxation/neuro-biomechanical dysfunction” for the word “subluxation” if they continue to imply that such disturbances can affect the nervous system to cause illness. A chiropractic subluxation by any other name is still a chiropractic subluxation.

Real and imaginary benefits of spinal manipulation

Recent reviews of the literature indicate that manipulation may not be any more effective than other treatment methods in affecting the ultimate outcome in recovery from back pain. For symptomatic relief of uncomplicated mechanical-type back pain, however, use of hands-on manipulation may provide more immediate and dramatic relief by stretching tight muscles and mobilizing the spine. Apart from the misinformation provided by chiropractors who keep asymptomatic patients coming back for correction of “subluxations” alleged to cause a myriad of health problems, many back-pain patients return for manipulative treatment for the symptomatic relief they experience. A competent chiropractor would release the patient when back-pain symptoms have resolved, as opposed to subluxation-based chiropractors who lock their patients into lifetime “subluxation correction” as a preventive measure. Endorsement of the use of manipulation in the treatment of mechanical-type back pain is not an endorsement of chiropractic adjustments used to correct subluxations or some other “joint disturbance” alleged to cause illness or poor health.

In rare cases involving articular adhesions, actual locking of a vertebral joint, or post-traumatic loss of mobility in spinal joints, there is no substitute for appropriate manipulation. Recognizing this, physical therapists and orthopedic manual therapists are now including use of manipulation in their treatment armamentarium.

In addition to the effect of mobilization and manipulation in relieving uncomplicated mechanical-type back pain and restoring mobility in spinal joints, there are additional effects produced by “popping” the vertebrae.

When vertebrae are manipulated to produce a popping sound, there is a slight separation of joint (facet) surfaces, producing a vacuum that pulls in nitrogen gas from joint or synovial fluids to fill the space. This is called “cavitation,” an effect that temporarily increases mobility and range of motion. Such an effect may produce a sense of well being, which seems compelling for some people. There might also be some slight temporary increase in height as a result of cavitation and decompression of disc cartilage.

Persons who believe that they have subluxations or vertebrae out of place causing a health problem may be subject to a powerful placebo effect when the spine is popped, leading them to believe that their condition is being helped or cured by replacement of a vertebra. Such popping does not mean that a vertebra was out of place. Normal vertebrae can be popped when thrust-type manipulation forces movement of spinal joints into the paraphysiologic space (beyond the normal range of movement).

After vertebrae have been manipulated to produce cavitation, it may take three or four hours for the joint surfaces to settle back together so that the vertebrae can be popped again. This popping sound may produce fear that failure to get regular adjustments to pop or align the vertebrae will result in development of illness─a nocebo effect often exploited by chiropractors who have asymptomatic patients coming back on a regular basis for “preventive maintenance.”

Alternative medicine: A refuge for chiropractic

In view of increasing opposition to subluxation theory, some chiropractic colleges have read the handwriting on the wall and moved into the camp of alternative medicine. The National University of Health Sciences (NUHS), for example, often referred to as the foremost American chiropractic college, offers Doctor of Chiropractic, Doctor of Naturopathic Medicine, Master of Science in Acupuncture, and Master of Science in Oriental Medicine degrees. NUHS recently announced a new cooperative arrangement with the Graduate Program in Complementary and Alternative Medicine at Georgetown University Medical Center in Washington D.C. Faculty at the two schools will work together to help students seeking advanced degrees in health care by advising students of the benefits of each other’s programs and providing preferential seating and advanced standing in each other’s programs when appropriate.

The web site of the Association of Chiropractic Colleges, in its “What Is Chiropractic?” section, states: “Because of the emphasis on holistic health care, chiropractic is associated with the field of complementary and alternative medicine.” (Accessed December, 13, 2011) Most health-care professionals consider “alternative medicine” to be a haven for unproven and implausible treatment methods.

Few consumers are aware of the great diversity in chiropractic, and few know what questions to ask when looking for a science-based chiropractor. Until all chiropractic colleges uniformly renounce the vertebral subluxation theory and are upgraded to training musculoskeletal specialists, treatment methods will vary from one chiropractor to another, incompatible with exchange in mainstream health care. With increasing numbers of physical therapists using high velocity, low amplitude thrust-type manipulation, physicians and other health-care providers can refer a patient to physical therapy for spinal manipulation, thus avoiding the problems associated with finding a chiropractor who uses manipulation appropriately.

In observing the web sites and promotional materials of newly graduated chiropractors, it appears that many of these chiropractors are combining science and pseudoscience to support treatment methods based on the basic tenets of traditional chiropractic, that is, manipulating the spine for some unverifiable neurological effect that will affect general health or organ function. Some, claiming to be primary care providers, combine “spine care” with “health care” and “wellness care” in a holistic approach that entails treatment and prevention over a broad scope of ailments, using a variety of alternative healing methods. Legislation to allow chiropractors with an “advanced practice” certification to prescribe drugs from a limited formulary has been proposed in New Mexico, South Carolina, and Alabama. Chiropractors would be required to have 90 hours of additional training in pharmacology. So far, such legislation, opposed by chiropractors who feel that chiropractic should remain a drugless healing profession defined by the basic principles of chiropractic, has failed.

Chiropractic and physical therapy are not the same

The only thing unique about chiropractic is its basic definition as a method of adjusting vertebral subluxations to restore and maintain health. Any other physical treatment method, including generic spinal manipulation, is physical medicine. The subluxation theory has been the chiropractic profession’s only reason for existence since its inception in 1895. Failure of the profession to establish itself as a legitimate physical-treatment specialty with an armamentarium that includes use of generic spinal manipulation continues to leave the profession dependent upon the basic tenets of chiropractic. Many chiropractors feel that if the chiropractic profession discards the subluxation theory and specializes in the care of back pain and related musculoskeletal problems, it will not be able to compete with physical therapists and other musculoskeletal practitioners who use manual therapy.

With a foundation based on an implausible theory that nurtures a hodgepodge of dubious chiropractic techniques, the chiropractic profession is splintered by philosophies that go in many different directions. The approach of chiropractic colleges may range from “straight chiropractic,” which proposes that most ailments can be treated by adjusting vertebral subluxations, to “alternative medicine,” which permits use of unproven treatment methods to treat a broad scope of ailments without resorting to subluxation theory.

It’s important to understand that manipulation used in the context of chiropractic subluxation theory is not done for the same reasons guiding the use of manipulation by physical therapists. With the exception of a few science-based chiropractors who use manipulation appropriately, it appears that most chiropractors manipulate or adjust putative vertebral subluxations in a misguided effort to restore and maintain health. Physical therapists use manipulation-mobilization primarily to restore mobility in the spine. When chiropractors accuse physical therapists of stealing their treatment method, nothing could be further from the truth. Generic spinal manipulation has long been a part of physical medicine and is unrelated to subluxation-based chiropractic. Chiropractors often say that the difference between physical therapists and chiropractors is that chiropractors adjust vertebrae while physical therapists manipulate the spine.

Entrenched subluxation theory
There is no reason to believe that the subluxation theory will ever be discarded by all chiropractors. Unable to demonstrate that real orthopedic subluxations can cause organic disease, some chiropractors refer to a “vertebral subluxation complex,” another name for a chiropractic subluxation that is asymptomatic and undetectable. Belief systems cannot be eradicated by scientific presentations, especially subluxation-based chiropractic which finds support in the pseudoscience of alternative medicine. It seems unlikely that chiropractic, tainted by subluxation theory, will ever be absorbed by physical therapy, become a subspecialty of medicine, or be welcomed by academia. It may already be too late for the chiropractic profession to make the changes needed to train chiropractors to do what physical therapists, physiatrists, and orthopedic manual therapists are already doing. It certainly does not seem likely that the chiropractic profession, as it stands today, could take the path chosen by osteopathy in 1929 when the federal government gave the osteopathic practitioner the same privileges granted to medical doctors.

In the final analysis, we see only what we are ready to see, what we have been taught to see. We eliminate everything that is not part of our prejudices.

— Jean-Martin Charcot, 1825-1893



  • Samuel Homola is a retired chiropractor who has been expressing his views about the benefits of appropriate use of spinal manipulation (as opposed to use of such treatment based on chiropractic subluxation theory) since publication of his book Bonesetting, Chiropractic, and Cultism in 1963. He retired from private practice in 1998. His 15 published books include Inside Chiropractic, published by Prometheus Books in 1999.

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Posted by Sam Homola

Samuel Homola is a retired chiropractor who has been expressing his views about the benefits of appropriate use of spinal manipulation (as opposed to use of such treatment based on chiropractic subluxation theory) since publication of his book Bonesetting, Chiropractic, and Cultism in 1963. He retired from private practice in 1998. His 15 published books include Inside Chiropractic, published by Prometheus Books in 1999.