The Chiropractic Subluxation 
and Adjustment

Theodosius Dobzhansky (1900-1975) was a highly influential Ukrainian-born American geneticist and evolutionary biologist. As one of the most important 20th-century biological scientists, he made evolutionary biology a rigorous, genetically grounded science. In a 1973 publication, he famously stated (1):

“Nothing in Biology Makes Sense Except in the Light of Evolution”

This dictum is memorialized in the Mosaic Medallion in the Floor of the Main Hall of the Jordan Hall of Science at the University of Notre Dame.

Dr. Dobzhansky died of leukemia in 1975, working until his last day as a Professor of Genetics at the University of California, Davis. Following his wisdom, there must be an evolutionary biological evolution explanation for the existence of the chiropractic subluxation.

Evolutionary Biology and the Chiropractic Subluxation

Historian Susan Wise Bauer taught American literature at the College of William and Mary. In her 2026 book, The Great Shadow, A History of How Sickness Shapes What We Do, Think, Believe, and Buy, she reviews the history of sickness and civilization (2). She reminds the reader, as do countless other publications, that up to the mid twentieth century (around 1950, a mere 75 years ago), people in developed countries stopped dying primarily from infections and began to die primarily from chronic illnesses like cardiovascular disease and cancer. Through today, there are regions of our world where people still primarily die from infections. 

In all human history, except for a few developed countries in the last approximately 75 years, humans died from infection. Since infections kill young people of child-bearing age, evolutionary biology required genetic adaptations to ensure the perpetuation of the human species.

These genetic adaptations (selections) are detailed in a vast range of publications. A convenient and easily accessible source to learn the biological importance of the adaptations are found in learned treatises on pathology. 

These publications on pathology are emphasized in orthopedic training because the genetic adaptations (selections) to enhance survivability from an infection create long-term orthopedic and hence ortho-neuro problems that modern clinicians manage, including chiropractors. A handful of these publications are woven into the publication below.

•••••

The June 2015 issue of the journal Scientific American has an article by primary care physician Wajahat Z. Mehal, MD, titled (3):

Cells on Fire

In this article, Dr. Mehal notes that infections initiate an inflammatory cascade that results in two physiological responses required for the infected person to survive, giving them an opportunity to make the next human generation:

• Activate the innate immune response.
• Activate fibroblasts/fibrocytes to create a fibrous response in an effort to “wall-off” the microbes, reducing their dissemination throughout the body while giving the adaptative immune response an opportunity to optimize.

In this scenario, the initial “walling-off” of pathogens is critical because it takes approximately 5-7 days for the elite fighters of the adaptative immune response to “kick-in.” Without this quick “walling-off” response, there is an increased risk of death in the first 5-7 days. In other words, quickly “walling-off” with a fibrosis is a mechanism that increases host survival, a response that is then passed on to future generations.

This inflammation-driven fibroblastic “walling-off” reduces pathogenic microbes from spreading in the body. Yet, as discussed below, non-infectious inflammation, like from injury or chronic tissue stress, will also cause a fibrous response. This fibrosis response is often referred to as “the fibrosis of repair.” This non-infectious fibrosis response functions differently both mechanically and neurologically, often resulting in the symptoms and signs of neuro-musculoskeletal dysfunction.

The consequences of tissue damage and/or excessive tissue stress can result in chronic inflammation and fibrosis, resulting in mechanical musculoskeletal problems. Chronic inflammation can be mechanically deleterious, serving no useful purpose. Dr. Mehal calls such inflammation sterile inflammation.

Decades before, in 1970, William Boyd, MD, published the eighth edition of his reference text, titled (4):

PATHOLOGY
Structure and Function in Disease

In chapter 4, titled “Inflammation and Repair,” Dr. Boyd states:

“Inflammation is the most common, the most carefully studied, and the most important of the changes that the body undergoes as the result of disease.”

Dr. Boyd notes that in chronic inflammation, the “only cells that proliferate are the fibroblasts.” Consequently, the chronic inflammatory response is a “fibroblast reaction,” or “fibrosis.” The lesion of chronic inflammation becomes increasingly fibrous as the collagen is laid down. The resulting fibrosis is much more marked than in acute inflammation situations. Also, the “newly formed fibrous tissue invariably contracts as it becomes older.”

Without doubt, this physiological fibrotic response is a component of the chiropractic subluxation complex.

In 1976, physicians WAD Anderson, MD, and Thomas Scotti, MD, published the ninth edition of their book, titled (5):

Synopsis of Pathology

In chapter 3 of their text “Inflammation and Repair,” they state:

“Inflammation is the most common and fundamental pathological reaction.”

The agents leading to inflammation include “microbial, immunologic, physical, chemical, or traumatic.”

“Chronic inflammation is a process that is prolonged, and proliferation (especially in connective tissues) forms a prominent feature.”

“The proliferative activity, leading to the production of abundant scar tissue, may in itself be distinctly harmful.” 

“The final healed state is achieved by development of a connective tissue scar.”

In 1979, Stanley Robbins, MD, and Ramzi Cotran, MD, published the second edition of their book, titled (6):

PATHOLOGIC BASIS OF DISEASE

Like Boyd, Anderson and Scotti, Robbins and Cotran also title chapter 3 of their text “Inflammation and Repair.” Robbins and Cotran state:

“Inflammation serves to destroy, dilute, or wall-off the injurious agent.”

“[Tissues are replaced by] filling the defect with less specialized fibroblastic scar-forming tissue.”

“Reparative efforts may lead to disfiguring scars, fibrous bonds that limit the mobility of joints, or masses of scar tissue that hamper the function of organs.”

It is of particular interest to chiropractors that this cascade of inflammation and fibrosis may “limit the mobility of joints.”

In 2020, David Strayer, MD, PhD, and Jeffery Saffitz MD, PhD, published the eighth edition of Rubins Pathology: Mechanisms of Disease (7). Chapter 2 of their book is titled “Inflammation,” and chapter 3 is titled “Repair, Regeneration, and Fibrosis.” 

Drs. Strayer and Saffitz note:

“Inflammation is the systemic and local tissue response to injury.”
 
“From scarring to regeneration, damaged tissues heal in ways that ensure the organism’s immediate survival.”

“Although new collagen formation during repair is essential for restoring strength at the healing site, fibrosis is a major complication of disease that involves chronic injury.”

“Excessive collagen deposition leads to fibrosis.” 

“The predominant mode of adult repair results in scar formation.”

“Scarring occurs particularly where there is greater mechanical movement and tension, such as over limb joints.”

“Scarring is a survival mechanism, with roles in tissue repair, isolating foreign invaders, and limiting injury.”

In 1982, orthopedic surgeon Sir James Cyriax, MD, published the eighth edition of his book titled (8):

Textbook of Orthopaedic Medicine:
Diagnosis of Soft Tissue Lesions

In this text, Dr. Cyriax notes that harmful infections create tissue destruction, resulting in inflammation. Our body recognizes this inflammation and attempts to “wall off” the infectious pathogens by creating a fibrous response. Cyriax states:

“The excessive reaction of tissues to an injury is conditioned by the overriding needs of a process designed to limit bacterial invasion.  If there is to be only one pattern of response, it must be suited to the graver of the two possible traumas.  However, elaborate preparation for preventing the spread of bacteria is not only pointless after an aseptic injury, but is so excessive as to prove harmful in itself. The principle on which the treatment of post-traumatic inflammation is based is that the reaction of the body to an injury unaccompanied by infection is always too great.”

Again, a link is expressed between infection, inflammation, and excessive-harmful tissue fibrosis.

In 1983, physicians Steven Roy and Richard Irvin published their book on sports injury titled (9): 

Sports Medicine:
Prevention, Evaluation, Management, and Rehabilitation

In this book, Roy and Irvin state:

“It is important to realize that the body’s initial reaction to an injury is similar to its reaction to an infection. The reaction is termed inflammation and may manifest macroscopically (such as after an acute injury) or at a microscopic level, with the latter occurring particularly in chronic overuse conditions.”

In 1986, physician and physiologist, Arthur Guyton, MD, published the seventh edition of his book, titled (10):

Textbook of Medical Physiology

Dr. Guyton states:

“One of the first results of inflammation is to ‘wall off’ the area of injury from the remaining tissues.”

“This walling-off process delays the spread of bacteria or toxic products.”

Guyton also expresses the concept of a sequential link between infection, inflammation, and fibrosis. This fibrosis, in the absence of infection, creates excessive mechanical impairments that are both mechanically and neurologically deleterious to the individual.

In 1992, physician I. Kelman Cohen and associates published their book titled Wound Healing, Biochemical & Clinical Aspects (11), in which they state:

“There are two important consequences of being a warm-blooded animal. One is that body fluids make optimal culture media for bacteria. It is to the animal’s advantage, therefore, to heal wounds with alacrity in order to reduce chances of infection.”

“The prompt development of granulation tissue forecasts the repair of the interrupted dermal tissue to produce a scar.” 

In addition to providing tensile strength, scars are believed to be a barrier to infectious migration.

•••••

These publications support that inflammation is universal and a paradox. Inflammation can neutralize pathogens. Inflammation also triggers a fibrous response that walls-off infection so that the pathogens are less likely to spread and kill the host. Without inflammation and fibrosis we would die of infection. People living today had ancestors that could successfully initiate an inflammatory response, kill pathogens, and wall off the pathogens. Those ancestors have passed on to us those genetic traits, evolutionary biology.

Infection can kill the young before they can reproduce. Hence, a strong inflammatory response is genetically selected, giving those with such a response a survivability advantage against infection. Our ancestors genetically handed down these traits and we possess them. In a world prior to the availability of antibiotics, inflammation, with reactive walling-off fibrosis to contain pathogens, is desirable because it increases host survivability.

Infection is not the only cause of inflammation. Inflammation is also triggered by trauma and/or excessive tissue stress. The body cannot distinguish the different causes of inflammation from each other, and they all trigger a fibrous response. “The resolution of inflammation in the body is fibrosis.”

This fibrosis response is necessary when there is an infection; it is life-saving. However, in an aseptic sterile injury or tissue stress, the fibrous response is excessive and it creates adverse mechanical deficits, including the entity that chiropractors term the “subluxation complex.” These mechanical deficits create tissue stiffness and limit the mobility of joints. These mechanical deficits impair local biomechanical function, affecting performance, generating pain, and accelerating degenerative changes. 

The management of adverse tissue fibrosis creates the pathoanatomical basis for mechanical based health care disciplines, including chiropractic and the adjustment of the subluxation. 

Support for the value in using motion to treat soft-tissue injuries has been in the literature for decades. As an example, Beverly Hills neurosurgeon Emil Seletz noted in the Journal of the American Medical Association in 1958 (12):

“During injury, hemorrhage within the capsular ligaments gives rise to swelling of the nerves and eventually adhesions between the dural sleeve and the nerve root; these factors give rise to symptoms that may be prolonged for months or even years after the injury.” 

“In reviewing the types of treatment with a number of specialists in this field, it is found that, while therapy naturally varies to suit the individual need, it consists primarily of local heat in the form of hot wet packs and cervical traction, followed by very gentle massage and manual rotations.”

“The importance of a carefully planned scheme of treatment must be emphasized to the patient, and treatments must be religiously carried out daily during the first two or three weeks (and then about three times weekly), depending, of course, on the individual case.”

“Delay or faulty treatment leads to adhesions about the facets and scarring about the capsular ligaments, persistent spasm, congestive lymph edema, and fibrosis of muscles, swelling, and eventual adhesions of nerves within the nerve root canals.”

“I cannot too strongly emphasize the urgency of early and persistent therapy, always by a specialist in this field.”

“Occasionally, a patient is seen with persistent complaints of head, neck, and shoulder pain, who has had on surgical exposure persistent swelling and adhesions of several nerve roots within the dural sleeve of exit.  It is most likely that early, persistent, and adequate therapy by those expertly trained in physical medicine will prevent most patients from developing a surgical condition.” 

On this topic, Cyriax’s (8) comments include a review of the 1940 primary research by ML Stearns (13), stating:

“Her [Stearns] main conclusion on the mechanics of the formation of scar tissue was that external mechanical factors were responsible for the development of the fibrillary network into orderly layers. Within four hours of applying a stimulus, an extensive network of fibrils was already visible around the fibroblasts; during the course of 48 hours this became dense enough to hide the cells almost completely: and in 12 days a heavy layer of fibrils had appeared. At first the fibrils developed at random, but later they acquired a definite arrangement, apparently as a direct result of the mechanical factors. Of these factors, movement is obviously the most important and equally obvious as it is most effective and least likely to cause pain before the fibrils have developed an abnormal firm attachment to neighboring structures. When free mobility was encouraged from the onset, the fibers in the scar were arranged lengthwise as in a normal ligament. Gentle passive movements do not detach fibrils from their proper formation at the healing breach but prevent their continued adherence at normal sites. The fact that the fibrils rapidly spread in all directions provides sufficient reason for beginning movements at the earliest possible moment; otherwise, they develop into strong fibrous scars (adhesions) that so often cause prolonged disability after a sprain.” 

Cyriax also notes (8):

“When non-bacterial inflammation attacks the soft tissues that move, treatment by rest has been found to result in chronic disability, later, although the symptoms may temporarily diminish.  Hence, during the present century, treatment by rest has given way to therapeutic movement in many soft tissue lesions. Movement may be applied in various ways: the three main categories are: (a) active and resistive exercises; (b) passive, especially forced movement [consistent with chiropractic adjustments]; (c) deep massage.”

“Tension within the granulation tissue lines the cells up along the direction of stress. Hence, during the healing of mobile tissues, excessive immobilization is harmful. It prevents the formation of a scar strong in the important direction by avoiding the strains leading to due orientation of fibrous tissue and also allows the scar to become unduly adherent, e.g. to bone.” 

In 1983, sports physicians Steven Roy and Richard Irvin note (9):

“The injured tissues next undergo remodeling, which can take up to one year to complete in the case of major tissue disruption. The remodeling stage blends with the later part of the regeneration stage, which means that motion of the injured tissues will influence their structure when they are healed. This is one reason why it is necessary to consider using controlled motion during the recovery stage. If a limb is completely immobilized during the recovery process, the tissues may emerge fully healed but poorly adapted functionally, with little chance for change, particularly if the immobilization has been prolonged.  Another reason for encouraging controlled motion is that any adhesions that develop will be flexible and will thus allow the tissues to move easily on each other.”

In 1986, physician John Kellett notes (14):

Acute inflammation is beneficial when one has acute infection. However, the “acute inflammatory phase of the body’s response to trauma is apparently of no benefit.” 

“Healing of ligaments and soft tissue injuries in general has been shown to occur by fibrous repair (scar tissue) and not by regeneration of the damaged tissue.”

“Early mobilization, guided by the pain response, promotes a more rapid return to full activity.” 

“Early mobilization, guided by the pain response, promotes a more rapid return to full functional recovery.” 

“The collagen is remodeled to increase the functional capabilities of the tendon or ligament to withstand the stresses imposed upon it.”

“It appears that the tensile strength of the collagen is quite specific to the forces imposed on it during the remodeling phase: i.e. the maximum strength will be in the direction of the forces imposed on the ligament.” 

Dr. Cohen (11) and associates also comment on the value of range of motion exercises in the management of soft tissue injury, stating:

“During the phase of wound contraction, the active cellular process is locked into position by increasing amounts of rigid collagenous scar. Frequent, gentle exercise can be used to put an extremity joint through a full range of motion and keep the newly developing scar tissue stretched and remodeled. Frequent use of the range of motion exercises is important to keep the developing and contracting scar tissue from becoming a rigid, fixed scar contracture. Range of motion exercises concentrate on remodeling the newly laid collagen before it develops into a rigid scar contracture.”

In 1994, Halldor Jonsson and associates (15) performed surgical evaluations of 50 patients with chronic whiplash symptoms, showing a “high incidence of discoligamentous injuries in whiplash-type distortions.” The authors noted:

“The injured spinal segments had become increasingly stiffer over 5 years, which may reflect healing of unrecognized soft tissue injuries.”

“The most likely source of radicular symptoms is perineural scarring. Therefore, patients with neck distortions after traffic accidents should be mobilized early within the limits of pain to prevent scar transformation of hidden injuries.”

In 2000, Pekka Kannus, MD, Ph.D., published a study in the journal The Physician and Sports Medicine, titled “Immobilization or Early Mobilization After an Acute Soft-Tissue Injury?” notes (16):

Prolonged inflammation may lead to excessive scarring.  Therefore, early, effective treatment seeks to prevent prolonged inflammation and excessive scarring.

“Experimental and clinical studies demonstrate that early, controlled mobilization is superior to immobilization for primary treatment of acute musculoskeletal soft-tissue injuries and postoperative management.” 

“The current literature on experimental acute soft-tissue injury speaks strongly for the use of early, controlled mobilization rather than immobilization for optimal heating.”

Experimentally induced ligament tears in animals heal much better with early, controlled mobilization than with immobilization. 

“The superiority of early controlled mobilization has been especially clear in terms of quicker recovery and return to full activity without jeopardizing the subjective or objective long-term outcome.” 

“Controlled experimental and clinical trials have yielded convincing evidence that early, controlled mobilization is superior to immobilization for musculoskeletal soft-tissue injuries. This holds true not only in primary treatment of acute injuries, but also in their postoperative management. The superiority of early controlled mobilization is especially apparent in terms of producing quicker recovery and return to full activity, without jeopardizing the long-term rehabilitative outcome. Therefore, the technique can be recommended as the method of choice for acute soft-tissue injury.”

Spinal manipulation is a form of passive controlled motion that mechanically influences more tissue than does either active or passive motions (17). Consequently, it is superior to other therapies in remodeling periarticular fibrosis and in reducing intra-articular adhesions. This noted by orthopedic surgeon Kirkaldy-Willis, MD (17):

In chronic cases [of back pain], there is a shortening of periarticular connective tissues and intra-articular adhesions may form; manipulations [adjustments] can stretch or break these adhesions.

“Spinal manipulation is essentially an assisted passive motion applied to the spinal apophyseal and sacroiliac joints.”

Conclusions

Adverse pathogens cause tissue destruction and subsequent inflammation. The body evolved in a manner to wall-off the area of inflammation by over healing the region with a fibrous response. The fibrous response becomes a physical barrier, reducing the ability of the pathogens to spread to other regions of the body, thereby improving the host’s chances for survival. However, when inflammation is caused by non-infectious mechanisms, the same fibrotic tissue response occurs. In such cases, without infectious pathogens, the fibrotic tissue response is excessive, resulting in mechanical harm to the host. This harmful tissue fibrosis is worsened with early immobilization of the affected tissues and minimized with early persistent controlled mobilization. Established harmful tissue fibrosis is best managed with specific controlled motion. Periarticular and intra-articular adhesions probably respond best to joint manipulation.

REFERENCES:

1. Theodosius Dobzhansky T; American Biology Teacher; March 1973; Vol. 35; No. 3; pp. 125-129.
2. Wise Bauer S; The Great Shadow, A History of How Sickness Shapes What We Do, Think, Believe, and Buy; St. Martin’s Publishing Group; 2026. 
3. Mehal WZ; Cells on Fire; Scientific American; June 2015; Vol. 312; No. 6; pp. 45-49.
4. Boyd W; PATHOLOGY: Structure and Function in Disease; Eighth Edition; Lea & Febiger; Philadelphia; 1970.
5. Anderson WAD, Scotti TM; Synopsis of Pathology; Ninth Edition; The CV Mosby Company; 1976.
6. Robbins SL, Cotran RS; PATHOLOGIC BASIS OF DISEASE; Second Edition; WB Saunders Company; Philadelphia; 1979.
7. Strayer D, Saffitz J; Rubins Pathology: Mechanisms of Disease; Eighth Edition; Lippincott Williams & Wilkins; 2020.
8. Cyriax J; Textbook of Orthopaedic Medicine, Diagnosis of Soft Tissue Lesions; Bailliere Tindall; Volume 1; eighth edition; 1982.
9. Roy S, Irvin R; Sports Medicine: Prevention, Evaluation, Management, and Rehabilitation; Prentice-Hall; 1983.
10. Guyton A; Textbook of Medical Physiology; Saunders; 1986.
11. Cohen IK, Diegelmann RF, Lindbald WJ; Wound Healing, Biochemical & Clinical Aspects; WB Saunders; 1992.
12. Seletz E; Whiplash Injuries, Neurophysiological Basis for Pain and Methods Used for Rehabilitation; Journal of the American Medical Association; November 29, 1958; pp. 1750–1755.
13. Stearns ML; Studies on development of connective tissue in transparent chambers in rabbit’s ear; American Journal of Anatomy; Vol. 67; 1940; p. 55.
14. Kellett J; Acute soft tissue injuries—a review of the literature;Medicine and Science in Sports and Exercise; October 1986;Vol. 18; No. 5; pp. 489-500.
15. Jonsson H, Cesarini K, Sahlstedt B, Rauschning W; Findings and Outcome in Whiplash-Type Neck Distortions; Spine; Vol. 19; No. 24; December 15, 1994; pp. 2733-2743.
16. Kannus P; Immobilization or Early Mobilization After an Acute Soft-Tissue Injury?; The Physician and Sports Medicine; March 2000; Vol. 26; No. 3; pp. 55-63.
17. Kirkaldy-Willis WH, Cassidy JD; Spinal Manipulation in the Treatment of Low back Pain; Canadian Family Physician; March 1985; Vol. 31; pp. 535-540.

“Authored by Dan Murphy, D.C. Published by ChiroTrust® – This publication is not meant to offer treatment advice or protocols. Cited material is not necessarily the opinion of the author or publisher.”