Spinal Manipulation, Chiropractic, and Subluxation Theory

Linda Rider

Vertebral Subluxations Do Not Affect General Health

The vertebral subluxation theory that gave birth to the chiropractic profession proposed that 95 per cent of diseases are caused by displaced vertebrae that place pressure on spinal nerves.1 Today, chiropractic is defined as a method of adjusting a “vertebral subluxation complex,” an asymptomatic and undetectable “joint dysfunction” (involving nerves, muscles, connective tissues, blood vessels, and other factors) alleged to influence organ system function and general health.2 There is no credible evidence to support the theory that joint dysfunction or a vertebral subluxation in any form can affect general health or cause internal organs to become diseased.

Spinal nerves are commonly compressed by bony spurs and herniated discs. Even the most severe compression of a spinal nerve, which may cripple the supplied musculoskeletal structures, does not cause organic disease. In the absence of fracture or pathology such as disc herniation or osteophyte formation, vertebral misalignments rarely affect spinal nerves.

Spinal nerves supply the sensory and motor (voluntary) functions of musculoskeletal structures. Involuntary function of the body’s organs is regulated by autonomic nerve ganglia and plexuses located outside the spinal column and by autonomic cranial and sacral nerves that pass through solid bony openings. The vagus nerves are autonomic (parasympathetic) cranial nerves that originate in the brain stem, traversing openings in the base of the skull to pass down through the neck, thorax, and abdomen to supply organs along their path. Preganglionic autonomic fibers, which emerge from the spinal cord and pass through spinal segments from the first thoracic vertebra to the second lumbar vertebra, terminate in sympathetic trunk and splanchnic ganglia located outside the spinal column. The vagus nerves along with autonomic ganglia and nerve plexuses provide overlapping sympathetic and parasympathetic nerve supply from many directions and sources (in concert with chemical, hormonal, and circulatory factors) to assure continued function of the body’s organs, independent of spinal nerves.3 This is why severance of the spinal cord in the neck area (at or above C4 to C5), shutting off brain impulses to spinal nerves, can cause paralysis of muscles from the neck down while the body’s organs continue to function. (Severance of the spinal cord above C5 can cause fatal respiratory paralysis.) Transplanted organs, reconnected with blood supply, function without reconnection of severed nerves.

Since the spinal cord ends at the level of the 2nd lumbar vertebra, spinal nerves pass down from the spinal cord (like the hair on a horse’s tail) to exit openings between the lumbar vertebrae and from openings (foramina) in the sacrum. Spinal nerves supplying bladder and bowel sphincter muscles pass through the solid bony openings of the sacrum (a pelvic bone at the bottom of the spine) and are not subject to compression by a subluxation. But they can be compressed by protrusion of a lower lumbar disc into the spinal canal, affecting voluntary control of bladder and anal sphincter muscles (cauda equina syndrome). This is a medical emergency that requires the immediate attention of a neurosurgeon. Spinal manipulation should not be done as a treatment for a herniated disc anywhere in the spine, especially in the lumbar spine where massive protrusions can occur.

Subluxation Theory Scientifically Indefensible but Still Going Strong

Spinal manipulation, massage, and other forms of manual therapy may have some neurological and physiological effects that might be beneficial in temporarily relieving back pain symptoms. But there is no evidence to indicate that such effects have a significant effect on general health.

A recent study by academic chiropractors 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.”4 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.”5

Despite the implausibility of chiropractic subluxation theory, state laws and chiropractic publications in the United States continue to define chiropractic as a method of correcting vertebral subluxations to restore and maintain health.7 A 2015 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.”7 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…a complex of functional and/or structural and/or pathological articular changes that compromise neural integrity and may influence organ system function and general health.”8

Manipulation as a Treatment Option

It’s important to understand that while a chiropractic adjustment based on subluxation theory has been rejected by the scientific community, spinal manipulation used in the treatment of mechanical-type back pain has a plausible basis that makes it acceptable in mainstream healthcare.

Birth of chiropractic

A 2011 Cochrane Systematic Review of spinal manipulative therapy for chronic low-back pain reported that “High-quality evidence suggests that there is no clinically relevant difference between SMT [spinal manipulative therapy] and other interventions for reducing pain and improving function in patients with chronic back pain.”9 A 2012 Cochrane review of spinal manipulative therapy for acute low-back pain concluded that “SMT…appears to be no more effective than other recommended therapies.”10 A 2012 National Center for Complementary and Alternative Medicine review of back-pain studies reported that “Overall, studies have shown that spinal manipulation is one of several options─including exercise, massage, and physical therapy─that can provide mild-to-moderate relief from low-back pain. Spinal manipulation also appears to work as well as conventional treatments such as applying heat, using a firm mattress, and taking pain-relieving medications.”11

Although some studies have indicated that spinal manipulation may not be more effective than a variety of other treatment methods for relieving back pain, many manual therapists know from experience that spinal manipulation can, on rare occasions, provide dramatic and permanent relief when manipulation restores mobility by breaking down adhesions or by unlocking binding vertebral facets. In my own practice as a chiropractor, I had many patients who simply loved a back-cracking back rub. Despite the controversy surrounding the use and effects of spinal manipulation, generic spinal manipulation deserves a place as an option in the armamentarium of physical medicine.

Aside from physical effects, spinal manipulation has powerful placebo and nocebo effects that perpetuate such treatment beyond reasonable use. Manipulation can produce popping sounds (cavitation) in normal joints. Such popping is not considered to be significant, but it can have a powerful placebo effect among those who believe that the popping sound signals correction of a dangerous subluxation. Unfortunately, some chiropractors allow their patients to believe that a popping sound means that vertebral subluxations are always present, producing a nocebo effect that lures fearful chiropractic patients and their families into a program of regular spinal adjustments in order to maintain health by keeping their vertebrae aligned.

It goes without saying that the cartilaginous, immature spine of an infant or a preadolescent child should never be “adjusted,” as some chiropractors are doing in a misguided effort to correct “subluxations,” risking injury to vertebral growth centers.12,13

Chiropractic Has the Confusing Image of a Back Specialty Capable of Treating a Broad Scope of Ailments

Although the public generally thinks of chiropractors as back specialists, few chiropractors limit their care to treatment of back pain. The vague and all-inclusive chiropractic subluxation theory generates a hodgepodge of entrepreneurial techniques and treatment methods for a variety of ailments. Few consumers are aware of the great diversity in chiropractic, and few know that it is important to seek a chiropractor who has rejected subluxation theory. Unfortunately, such chiropractors are hard to find. Treatment techniques vary from one chiropractor to another among subluxation-based chiropractors. Some chiropractors use a spring-loaded mallet to tap vertebrae in place in order to “restore the integrity of the nervous system.” Upper cervical chiropractors believe that aligning the atlas (the vertebra at the top of the spine) will “influence the central nervous system and brain stem function,” curing disease as well as relieving back pain.14

Note: Upper cervical manipulation has been associated with stroke caused by injury to vertebral and carotid arteries. Neck manipulation should not be done except in the case of a carefully selected mechanical-type neck problem in which use of manipulation, like mobilization, does not involve rotating the head to force rotation of upper cervical structures beyond normal ranges of movement (into the paraphysiologic joint space), stretching vertebral arteries in the atlanto-axial area. Risk certainly outweighs benefit when any neck manipulation is based on correction of a putative chiropractic subluxation.15,16

Web promotions by recent graduates of chiropractic colleges, parroting subluxation verbiage, emphasize “spine care” in combination with a variety of subluxation-based treatment methods. These chiropractors may claim to be primary care providers with a holistic approach that entails treatment and prevention of the gamut of human ailments, using a variety of unproven and implausible alternative healing methods.

Note: The University of Pittsburg offers a program that certifies chiropractors and physical therapists as Primary Spine Practitioners (PSP) who specialize in the treatment or the need for referral of spine-related disorders, sans subluxation theory.17

According to the Association of Chiropractic Colleges, “Doctors of chiropractic are primary care professionals for spinal health and well being …who are concerned with the diagnosis, treatment and prevention of disorders of the musculoskeletal system and effects of such disorders on the nervous system and overall health.”18 With a vague definition suggesting that musculoskeletal problems (not ruling out vertebral subluxations) can affect the nervous system to cause a health problem, the chiropractic profession has not chosen to seek development as a scientifically acceptable musculoskeletal specialty, despite the fact that back pain and musculoskeletal conditions are the No. 1 and No. 2 causes of disability worldwide.19

Some chiropractic colleges offer decent instruction in the care of musculoskeletal problems but may be tainted by subluxation theory or by alternative medicine methods (such as functional medicine or acupuncture) that encompass a broad scope of ailments. A few chiropractic colleges that have backed away from subluxation theory remain on shaky ground by including the subject of alternative medicine in their curriculum. Without uniform licensure of chiropractors, with standardization of treatment methods as a musculoskeletal specialty, a science-based, properly-limited chiropractor who openly renounces subluxation theory will continue to be an anomaly, and appropriate use of spinal manipulation will remain in the domain of physical therapy and physical medicine.

Without changes in state laws and the curriculum of chiropractic colleges, the chiropractic profession will remain dependent upon subluxation theory for its existence.

Subluxation Theory Perpetuated as a Belief System

There are no indications that the nonfalsifiable subluxation theory, the foundation of chiropractic, will ever be discarded by all chiropractors. With no plausible or scientific rationale to support it, subluxation theory, based on the tenets of a founding father, will be perpetuated as a belief system, as in the case of homeopathy and traditional osteopathy. Chiropractic subluxations that are not detectable by conventional methods are allegedly being located (only by chiropractors) by such dubious procedures as thermography, applied kinesiology, and leg-length checks.

Consumers should be advised to avoid subluxation-based chiropractors who say “I do not diagnose or treat disease. I simply remove nerve interference so that the body can heal itself.”

The Bottom Line

According to WebMD, 22 million Americans visit chiropractors annually. Of these, about 7.7 million are seeking relief from back pain.20 While spinal manipulation and physical therapy modalities may be helpful in the treatment of musculoskeletal problems, it is important to be on guard to avoid spinal manipulation or any treatment method based on subluxation theory.

There is no credible evidence to support use of spinal manipulation for anything other than uncomplicated mechanical-type back pain and related problems. It has never been demonstrated that a real orthopedic subluxation or a pinched spinal nerve can affect general health. An undetectable “vertebral subluxation complex” alleged to cause organic problems simply does not exist.

If you are looking for a chiropractor who treats back pain or a musculoskeletal problem, look for one who does not subscribe to subluxation theory and who combines use of generic spinal manipulation with physical therapy modaliities. A good science-based chiropractor is always willing to exchange office notes with your family physician. Remember that acute low-back pain, when it is mechanical in nature and not accompanied by fever or radiation down one leg, is often a self-limiting condition that will resolve in four to six weeks, with or without treatment. Appropriate treatment, however, can relieve symptoms, which may provide temporary but welcome relief that may reduce need for medication.

A correct diagnosis is essential when considering treatment options. When treatment for back pain or a health problem is based on a “subluxation complex” diagnosis, unnecessary chiropractic adjustments will delaying appropriate treatment based on a correct diagnosis and may lock the patient into ongoing preventive-maintenance spinal manipulation. Remember that a “subluxation complex” alleged to cause health problems is asymptomatic and undetectable, thus nonexistent, as opposed to an orthopedic subluxation which causes musculoskeletal symptoms and is detectable on physical and x-ray examination.


1. Palmer, Daniel David. 1910. <em>The Chiropractor’s Adjuster: A Textbook of the Science, Art, and Philosophy of Chiropractic for Students and Practitioners</em>. Portland, Oregon. Portland Printing House.

2. Association of Chiropractic Colleges. Chiropractic Paradigm. http://www.chirocolleges.org/paradigm_scope_practice.html

3. Homola, Samuel. 2006. Chiropractic: History and Overview of Theories and Methods. <em>Clinical Orthopaedics and Related Research</em>. 444:236-242.

4. Mirtz, Timothy A., Lon Morgan, Lawrence H. Wyatt, et al. 2009. An epidemiological examination of the subluxation construct using Hill’s criteria of causation. <em>Chiropractic and Manual Therapies</em>. 17:13.

5. Mirtz, Timothy A., Stephen M. Perle. 2011. The prevalence of the term subluxation in North American English-Language Doctor of Chiropractic programs. Chiropractic and Manual Therapies. 19:14.

6. Bellamy, J.J. 2010. Legislative alchemy: The U.S. state chiropractic practice acts. <em>Focus on Complementary and Alternative Therapies</em>. 15(3):214-222.

7. Christensen, Mark G, Martin W. Kollasach, John K. Hyland, et al. 2015. <em>Practice Analysis of Chiropractic 2015</em>. Greeley, Colorado; National Board of Chiropractic Examiners.

8. CCE. An open letter to the profession from the Council on Chiropractic Education. November 22, 2011. http://www.acatoday.org/pdf/CCE_Letter.pdf

9. Rubinstein, Sidney M., Marienke van Middelkoop, Willem J.J. Assendelft, et al. 2011. Spinal manipulative therapy for chronic low-back pain. <em>Cochrane Database Systematic Review</em>. February 16. (2):CD0081123.

10. Rubinstein, Sidney M., Caroline B. Terwee, Willem J.J. Assendelft, Michiel R. de Boer, et al. 2012. Spinal manipulative therapy for acute low-back pain. <em>The Cochrane Library</em>. September 12. (2):CD008880.

11. National Center for Complementary and Alternative Medicine. 2012. Spinal manipulation for low-back pain: What the science says. NCCAM Clinical Digest. May. http://nccam.nih.gov/health/providers/digest/backpain-science.

12. Homola, Samuel. 2010. Should Chiropractors Treat Children? <em>Skeptical Inquirer</em>. 34(5):50-53

13. Homla, Samuel. 2016. Pediatric Chiropractic Care: The Subluxation Question and Referral Risk. <em>Bioethics</em>. 2016; 30(2): pp63-68.

14. Homola, Samuel. 2009. The problem with chiropractic NUCCA. Science-Based Medicine. August 7. http://www.sciencebasedmedicine.org/index.php/the-problem-with-chiropractic-nucca/

15. Homola, Samuel. 2009. Neck Manipulation: Risk vs. Benefit. Science-Based Medicine. August 27. http://www.sciencebasedmedicine.org/neck-manipulation-risk-vs-benefit/

16. Homola, Samuel. 2014. Neck manipulation, stroke and the precautionary principle. <em>Focus on Alternative and Complementary Therapies</em>. 19(4):208-211.

17. Primary Spine Practitioner Certification Program. University of Pittsburg. www.psp.pitt.edu

18. Association of Chiropractic Colleges. What is Chiropractic? http://www.chirocolleges.org/about-chiropractic/2023

19. Vos, Theo, Abraham D. Flaxman, Mohsen Naghavi, et al. 2012. Years lived with disability (YLDs) for 1160 sequelae of 289 diseases and injuries 1990-2010: a systematic analysis of the Global Burden of Disease Study 2010. The Lancet. 380(9859):2163-2196.

20. Skarnulis, Leona. 2022. Chiropractic Care for Back Pain. WebMD. https://www.webmd.com/back-pain/guide/chiropractic-pain-relief/

  • 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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