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Vertebral subluxation is a chiropractic term that is used by chiropractors to describe a myriad of signs and symptoms thought to occur as a result of a misaligned or dysfunctional spinal segment. Since its conception by DD Palmer, the definition has undergone many refinements in an effort to describe the conditions that chiropractors treat. In 1996, the Association of Chiropractic Colleges, representing all chiropractic colleges, unified the definition as, "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."

The concept of chiropractic vertebral subluxation remains a chiropractic construct that does not enjoy mainstream medical support. It should not be confused with the orthopedic subluxation. While the orthopedic and medical definition of a subluxation includes misalignment and sometimes nerve damage, it is considered an uncommon occurrence.

Introduction

Chiropractors propose that a vertebral subluxation can negatively affect general health by altering the proper circulation of information via the nervous system. Although not always painful, chiropractors claim that a subluxation interferes with the proper function and healing of your body due to the role of the nervous system as a controller of many bodily functions.

A vertebral subluxation is theorized to affect one spinal disc (i.e. degenerative disc disease), a section of the spine, or the entire spine. For example, a functional scoliosis or abnormal curvature of the spine, viewed in chiropractic terms, may be due to a subluxation of one vertebra that causes a distortion of the entire spine.

There is marginal evidence that the chiropractic vertebral subluxation influences the nervous system as the original chiropractic theory asserts.

Chiropractic treatment of vertebral subluxation focuses on delivering a chiropractic adjustment to the affected part of the spine in an effort to reduce the subluxation. Spinal manipulation is the primary procedure used by chiropractors in the adjustment. It has been shown to help some symptoms of subluxations such as low back pain, neck pain and tension type headaches, but there are no clinically controlled studies to evaluate the effects on organ function.

Historical definitions

"The possible neurological consequences of subluxation were described by Harrison in 1821, as quoted by Terrett:“When any of the vertebrae become displaced or too prominent, the patient experiences inconvenience from a local derangement in the nerves of the part. He, in consequence, is tormented with a train of nervous symptoms, which are as obscure in their origin as they are stubborn in their nature...”"

In the chiropractic system developed by Daniel D. Palmer in the late 1800's, Palmer originally believed that he had discovered the cause of all diseases suffered by mankind - the vertebral subluxation.

"Physiologists divide nerve-fibers, which form the nerves, into two classes, afferent and efferent. Impressions are made on the peripheral afferent fiber-endings; these create sensations which are transmitted to the center of the nervous system. Efferent nerve-fibers carry impulses out from the center to their endings. Most of these go to muscles and are therefore called motor impulses; some are secretory and enter glands; a portion are inhibitory their function being to restrain secretion. Thus, nerves carry impulses outward and sensations inward. The activity of these nerves, or rather their fibers, may become excited or allayed by impingement, the result being a modification of functionating—too much or not enough action—which is disease."

Chiropractors use and have used various terms to express this concept: subluxation, vertebral subluxation (VS), vertebral subluxation complex (VSC), "killer subluxations," the "silent killer," or a "bone out of place" (BOOP) .

Functional theory of vertebral subluxation

Vertebral subluxation
The formation of the spinal nerve from the dorsal and ventral roots
A spinal nerve with its anterior and posterior roots.
Details
Identifiers
Latin	radix posterior
Anatomical terminology[edit on Wikidata]

As a continuation of the brain, the spinal cord contains nerve tracts which are the neurological pathways through which the brain communicates with most of the body. While the brain is protected by the skull, the spinal cord is protected by the vertebral column. As nerves branch off the spinal cord, they form the spinal nerve roots which exit the vertebral column through an opening made by two adjacent vertebrae, called the intervertebral foramen.

V. Strang, D.C., describes several hypotheses on how a misaligned vertebra may cause interference to the nervous system in his book, Essential Principles of Chiropractic.

• Nerve compression hypothesis: suggests that when the vertebrae are out of alignment, the nerve roots and/or spinal cord can become pinched or irritated. While the most commonly referenced hypothesis, and easiest for a patient to understand, it may be the least likely to occur.
• Proprioceptive insult hypothesis: focuses on articular alterations causing hyperactivity of the sensory nerve fibers.
• Somatosympathetic reflex hypothesis: all the visceral organ functions can be reflexly affected by cutaneous or muscular stimulation.
• Somatosomatic reflex hypothesis: afferent impulses from one part of the body can result in reflex activity in other parts of the body.
• Viscerosomatic reflex hypothesis: visceral afferent fibers cause reflex somatic problems.
• Somatopsychic hypothesis: the effects of a subluxation on the ascending paths of the reticular activating system.
• Neurodystrophic hypothesis: focuses on lowered tissue resistance that results from abnormal innervation.
• Dentate ligament-cord distortion hypothesis: upper cervical misalignments can cause the dentate ligaments to put a stress on the spinal cord.
• Psychogenic hypothesis: emotions, such as stress, causing contraction in skeletal muscles.

The vertebral subluxation has been described as a syndrome with signs and symptoms which include: altered alignment; aberrant motion; palpable soft tissue changes; localized/referred pain; muscle contraction or imbalance; altered physiological function; reversible with adjustment/manipulation; focal tenderness.

The claims for the existence of vertebral subluxations are a matter of controversy, and the chiropractic concept is not recognized by mainstream medicine and science (JMPT, .) The Wilk v. American Medical Association trial transcripts mention this fact:

There was evidence that the chiropractic theory of subluxations was unscientific, and evidence that some chiropractors engaged in unscientific practices. The court did not reach the question of whether chiropractic theory was in fact scientific. However, the evidence in the case was that some forms of chiropractic manipulation of the spine and joints was therapeutic. AMA witnesses, including the present Chairman of the Board of Trustees of the AMA, testified that some forms of treatment by chiropractors, including manipulation, can be therapeutic in the treatment of conditions such as back pain syndrome.

Treatment of vertebral subluxation

When chiropractors believe a vertebral subluxation is present they may apply a specific adjustment to the spinal bone considered to be subluxated. While there are a number of different chiropractic techniques, each can be characterized by the description of having a short-lever, high velocity, low amplitude (HVLA) thrust and specific line of correction.

While chiropractors do attempt to direct treatment at specific movement segments of the spinal column, what separates the chiropractic adjustment from other manipulative techniques is the chiropractic intent - the treatment of vertebral subluxations. No other profession claims to have this intent.

Once these bones or vertebrae are theoretically restored to their proper position and/or motion, the spinal cord and/or its nerve roots are no longer considered to be hindered or compressed. Thus, without interference from a subluxation, the brain is considered to be enabled to transmit and receive all the messages through the spinal cord and nerve roots to all the parts of the body supplied by those nerves. The spine is considered "in line" and thus it is assumed the body functions in a coordinated manner resulting in increased health.

The traditional chiropractic hypothesis - that vertebral subluxations cause neurological interference that may result in disease, disorder, or dysfunction - remains controversial. Vertebral subluxation remains a hypothesis.

Scientific investigation of vertebral subluxation

The investigation of vertebral subluxation has been ongoing since it was first postulated in 1895. The early practioners used palpation and the anatomy of the nervous system as a guide (meric system). In their efforts to be more specific, they seized the newly discovered X-ray technology and introduced the neurocalometer (a heat sensing device). It was during those early years that the medical establishment first criticized the chiropractic profession, saying that the conditions that those early chiropractors were treating were only psychophysiologic disorders. To prove that chiropractic patients had real conditions, BJ Palmer opened a research clinic as a part of the Palmer College of Chiropratic. When a patient entered the clinic, they were first examined by medical doctors and a diagnosis was formulated. They were then sent to the chiropractic part of the clinic, treated, and sent back to the medical doctors for evaluation. Since then, chiropractors have sought a greater understanding of the mechanisms and effects of the vertebral subluxation. Today we see motion x-rays, surface EMG, and digital thermography.

"Conclusions: Joint complex dysfunction should be included in the differential diagnosis of pain and visceral symptoms because joint complex dysfunction can often generate symptoms which are similar to those produced by true visceral disease."

A 2004 reasearch team at the National University of Health Sciences evaluated changes of the lumbar vertebral column following fixation (immobility). Their findings indicate that fixation results in time-dependent degenerative changes of the zygapophysial joints.

Researchers at the RMIT University-Japan, Tokyo studied reflex effects of subluxation with regards to the autonomic nervous system. They found that "recent neuroscience research supports a neurophysiologic rationale for the concept that aberrant stimulation of spinal or paraspinal structures may lead to segmentally organized reflex responses of the autonomic nervous system, which in turn may alter visceral function."

Professor Philip S. Bolton of the School of Biomedical Sciences at University of Newcastle, Australia writes in JMPT, "The traditional chiropractic vertebral subluxation hypothesis proposes that vertebral misalignment cause illness, disease, or both. This hypothesis remains controversial." His objective was, "To briefly review and update experimental evidence concerning reflex effects of vertebral subluxations, particularly concerning peripheral nervous system responses to vertebral subluxations. Data source: Information was obtained from chiropractic or, scientific peer-reviewed literature concerning human or animal studies of neural responses to vertebral subluxation, vertebral displacement or movement, or both." He concluded, “Animal models suggest that vertebral displacements end putative vertebral subluxations may modulate activity in group I to IV afferent nerves. However, it is not clear whether these afferent nerves are modulated during normal day-to-day activities of living and, if so, what segmental or whole-body reflex effects they may have.”

Conclusions: Monitoring mixed-nerve root discharges in response to spinal manipulative thrusts in vivo in human subjects undergoing lumbar surgery is feasible. Neurophysiologic responses appeared sensitive to the contact point and applied force vector of the spinal manipulative thrust. Further study of the neurophysiologic mechanisms of spinal manipulation in humans and animals is needed to more precisely identify the mechanisms and neural pathways involved.

Researchers at the Department of Physiology, University College London studied the effects of compression upon conduction in myelinated axons. Using pneumatic pressure of varying degrees on the sciatic nerves of frog specimens, the studied supported the idea of nerve conduction failure as a result of compression.

A model for chronic nerve root compression studies.

History

In its chiropractic context, the term "subluxation" was first described by Daniel David Palmer, who was possibly inspired by osteopath Andrew Still. Still's model was a disturbance of blood flow to various organs from what he termed "osteopathic lesions", resulting in weakening of tissues and organs. Palmer's understanding, based on the scientific knowledge of the time, was that a disturbance of nerve supplies to the same tissues and organs more readily explained the changes produced after correction ("adjustments") of misaligned spinal bones.

The original investigation and research into this newly described entity are shrouded in confusion, due to lack of formal notes, and the political struggle that ensued to establish a stable fountainhead for the entire chiropractic profession. A popular version was that Palmer restored long-lost hearing to a janitor by realigning bones of his spine. Sources from the period claim that chiropractic as a treatment form gained notoriety during the 1918 Flu Epidemic, when it was alleged that patients receiving "adjustments" had significant lesser mortality than those treated with conventional medical treatments of the day.

Osteopath Irwin Korr investigated and said he confirmed the influence of nerve involvement in the mechanism of health and disease. However, osteopathic and chiropractic have diverged in their scope and focus. Whereas chiropractors have retained as their main goal the detection and correction of subluxations, osteopaths have shifted toward a more medical approach to care.

Both the osteopathic "subluxation" and the chiropractic "vertebral subluxation" remain hypotheses and are not universally accepted within their respective professions, much less outside of them.

Critiques

An area of debate among chiropractors is whether "vertebral subluxation" is a metaphysical concept (as posited in B. J. Palmer's philosophy of chiropractic) or a real phenomenon.

In an article on chiropractic vertebral subluxation written in 2005, the authors say:

"There is nothing inherently dogmatic or anti-scientific in the notion that an articular lesion may have health consequences, or that correction of joint dysfunction may relieve symptoms and/or improve health. Neither does our current inability to predict the effects (if any) of subluxation and/or the benefits of subluxation-correction relegate this hypothetical construct to the dustbin of clinical theories. Indeed, it would be just as inappropriate to dispose of this largely untested theory without data as it is to proclaim its meaningfulness without adequate evidence. On the other hand, as Carl Sagan suggested, extraordinary claims will require extraordinary evidence. With respect to the supposed mechanisms of adjusting, Haldeman reminds us that "What must be avoided... is the unreasonable extrapolation of current knowledge into speculation and presentation of theory as fact." Given the current deficiency of empirical data, the only sound scientific-epistemological position that we can conceive of is to acknowledge our ignorance: we don't know if subluxation is clinically meaningful or not. We suggest that this is a requisite first step toward greater wisdom concerning subluxation."

The concept of vertebral subluxation has been plagued with definitional problems since its inception. One of chiropractic's most staunch defenders of belief in the vertebral subluxation provides this explanation as a possible cause of the confusion:

The vertebral subluxation cannot be precisely defined because it is an abstraction, an intellectual construct used by chiropractors, chiropractic researchers, educators and others to explain the success of the chiropractic adjustment.

This is not a unique state of affairs, abstract entities populate many branches of science...

Subluxations, genes, gravity, the ego and life are all heuristic devices, "useful fictions" that are used to explain phenomenon that are far larger than our understanding. We use them as long as they work for us and discard or limit their application when they become unwieldy or unable to account for new observations...

Critics of chiropractic have incorrectly assumed that chiropractic is based on the theory or principle that vertebral subluxations cause "pinched" nerves that cause disease. They have it backwards. Chiropractic is based on the success of the spinal adjustment. The theory attempting to explain the success of the adjustment (nerve impingement, dis-ease, subluxations) followed its clinical discovery.

Examples of such erroneous criticisms based on this straw-man argument abound in the medical literature. Some examples: "The teachers, research workers and practitioners of medicine reject the so-called principle on which chiropractic is based and correctly and bluntly label it a fraud and hoax on the human race." "The basis of chiropractic is completely unscientific." The theory on which chiropractic is based , namely that a "subluxation" of a spinal vertebra presses on a nerve interfering with the passage of energy down that nerve causing disease to organs supplied by that nerve, and that chiropractic "adjustments" can alleviate the pressure thereby treating or preventing such disease. There is no scientific evidence for the validity of this theory."

To be fair, statements by some chiropractors have tended to perpetuate this misunderstanding: "Pressure on nerves causes irritation and tension with deranged functions as a result."

When chiropractors declare that "pinched nerves" "nerve impingement" "spinal fixations" or others mechanisms of action explain how subluxations affect the person and how chiropractic works they are making the same mistake medical critics make - assuming chiropractic is based on theory. Mechanisms and theories are useful tools, but their limitations should always be kept in mind. Koren

Whether one accepts the statement, "Subluxations, genes, gravity, the ego and life are all heuristic devices, "useful fictions" that are used to explain phenomenon that are far larger than our understanding," gravity and genes, unlike vertebral subluxations, have been empirically verified. At the present time, "vertebral subluxation" remains a metaphysical construct, posited by chiropractic's philosophy of disease, neither of which have been verified, submitted to double-blind tests, much less are capable of falsifification. Thus, confusion continues.

The concept of vertebral subluxation has been a source of contention throughout the history of the profession. It has drawn criticism from outside the profession, and has also created division and discussion within the profession. The following citation from within the profession sums up the problems:

"The dogma of subluxation is perhaps the greatest single barrier to professional development for chiropractors. It skews the practice of the art in directions that bring ridicule from the scientific community and uncertainty among the public. Failure to challenge subluxation dogma perpetuates a marketing tradition that inevitably prompts charges of quackery. Subluxation dogma leads to legal and political strategies that may amount to a house of cards and warp the profession's sense of self and of mission. Commitment to this dogma undermines the motivation for scientific investigation of subluxation as hypothesis, and so perpetuates the cycle."

References

1. Association of Chiropractic Colleges, Chiropractic Paradigm
2. Palmer DD (1910) The Science, Art and Philosophy of Chiropractic Portland, Oregon: Portland Printing House Company p20
3. Strang, V (1984) Essential Principles of Chiropractic Davenport : Palmer College of Chiropractic, OCLC: 12102972
4. Cramer G, Fournier J, Henderson C, Wolcott C. "Degenerative changes following spinal fixation in a small animal model". J Manipulative Physiol Ther. 27 (3): 141–54. PMID 15129196.{{cite journal}}: CS1 maint: multiple names: authors list (link)
5. Bolton P (2000). "Reflex effects of vertebral subluxations: the peripheral nervous system. An update". J Manipulative Physiol Ther. 23 (2): 101–3. PMID 10714535.
6. Colloca C, Keller T, Gunzburg R, Vandeputte K, Fuhr A (2000). "Neurophysiologic response to intraoperative lumbosacral spinal manipulation". J Manipulative Physiol Ther. 23 (7): 447–57. PMID 11004648.{{cite journal}}: CS1 maint: multiple names: authors list (link)
7. The effects of compression upon conduction in myelinated axons of the isolated frog sciatic nerve. R Fern and P J Harrison, Department of Physiology, University College London. J Physiol. 1991 January; 432: 111–122. available online
8. Keating J, Charlton K, Grod J, Perle S, Sikorski D, Winterstein J (2005) Subluxation: dogma or science? Chiropr Osteopat. 2005; 13: 17. available online

Further reading

• Reflex effects of vertebral subluxations: the peripheral nervous system. An update, Journal of Manipulative Therapeutics, Volume 23, Issue 2, Pages 101-103 (February 2000). Abstract.

• Foundations of Chiropractic: Subluxation, Meridel I. Gatterman, Mosby-Year Book, Inc., 1995, hardcover textbook, 487 pages, ISBN 0-8151-3543-2

External links

• Vertebral Subluxation in Chiropractic Practice - Council on Chiropractic Practice
• Models of Vertebral Subluxation:A Review - Christopher Kent, DC
• Journal of Vertebral Subluxation Research - A Peer-Reviewed Scientific Journal
• Chiropractic's Elusive Subluxation - Stephen Barrett, M.D.
• Does the Vertebral Subluxation Exist? - Tedd Koren, DC

• Chiropractic