What Really Is A Chiropractic “Adjustment”?

The June 2015 issue of the journal Scientific American has an article by primary care physician Wajahat Z. Mehal, MD, from the Department of Veterans Affairs Medical Center in Connecticut, and Yale University, titled (1):

Cells on Fire

In this article, Dr. Mehal notes that inflammation is set in motion by cells of the immune system, and that it is helpful because it kills pathogens and blocks their spread in the body. The inflammatory cascade, initiated by the innate immune response’s macrophages, weakens and immobilizes adverse microbes.

However, the same inflammatory cascade can occur when no microbes exist, triggered as a consequence of tissue damage and/or excessive tissue stress. This inflammatory response can, in-and-of-itself, become chronic and cause additional tissue damage. In other words, as much as acute inflammation can be beneficial (containing and/or killing pathogens), chronic inflammation can be deleterious, serving no useful purpose.

Consequently, Dr. Mehal broadly categorized the inflammatory response into two categories:

1) Infectious inflammation:

This is an inflammatory response that is designed to contain and/or kill pathogens.

This response is critical for individual and species survival.

2) Sterile inflammation:

This is an inflammatory response in which there are no associated pathogens, a response that is triggered by tissue injury and /or excessive tissue stress.

This response often becomes chronic. As such, this response is excessive and harmful.

Pathology History

A decades synopsis of global leading experts, expressed in leading reference texts printed by top medical publishers

In 1952, William Boyd, MD, Professor Emeritus of Pathology at the University of Toronto, published his reference text, titled (2):


Structure and Function in Disease

In this text, Dr. Boyd states:

“The inflammatory reaction tends to prevent the dissemination of infection. Speaking generally, the more intense the reaction, the more likely the infection to be localized.”

In 1970, the eighth edition of Dr. Boyd’s PATHOLOGY text is published

(3): 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 considered to be a “fibroblast reaction,” or “fibrosis.” The lesion of chronic inflammation becomes more and more 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.”


In 1976, physicians WAD Anderson, MD, and Thomas Scotti, MD, published the ninth edition of their book titled (4):

Synopsis of Pathology

Drs. Anderson and Scotti were Professors of Pathology at the University of Miami School of Medicine. Similar to Boyd, they title chapter 3 of their text “Inflammation and Repair,” in which 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.”

An important premise from Drs. Anderson and Scotti is that in chronic inflammation, “abundant” scar tissue may form, and this connective tissue scar may “itself be distinctly harmful.”


In 1979, Harvard Medical School professors Stanley Robbins, MD, and Ramzi Cotran, MD, published the second edition of their book, titled (5):


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

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

“Without inflammation, bacterial infections would go unchecked.”

But, “inflammation itself may be potentially harmful:”

Chronic inflammation is “generally of longer duration and is associated histologically with the presence of lymphocytes and macrophages and the proliferation of small blood vessels and fibroblasts.”

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 1982, orthopedic surgeon Sir James Cyriax, MD, published the eighth edition of his book titled (6):

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.”

Once 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 (7):

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 (8):

Textbook of Medical Physiology

At the time of publication, Dr. Guyton was Chairman and Professor of Physiology and Biophysics at the University of Mississippi School of Medicine. 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.”

Once again, Guyton expresses the concept of a sequential link between infection, inflammation, and fibrosis. This fibrosis, in the absence of inflammation, 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 (9), 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.


For more than half a century, experts in pathology, physiology, orthopedics, sports injuries, and wound healing have suggested the following model:

Inflammation is a paradox. Inflammation can directly kill 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 we would die of infection. All who are alive today had ancestors that could successfully initiate an inflammatory response, kill pathogens, and wall off the pathogens.

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. 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.

Infections were the primary cause of death for humans for millennias. Infections remained the primary cause of human death until very recent history, only a few decades ago.

Infection is not the only cause of inflammation. As noted above, inflammation is also triggered by trauma, excessive tissue stress, chemicals, and immunologic responses. Apparently, 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 necesasary 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. These adverse 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. Abnormal tissue fibrosis can be minimized with early, persistent, controlled motion. Once established, abnormal tissue fibrosis can be improved with the use of a variety of motion applications. 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, associated with the medical school at the University of California, Los Angeles (UCLA), noted in the Journal of the American Medical Association in 1958, the following, with respects to the management of whiplash soft-tissue injuries (10):

“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.”