The Mechanism of the Chiropractic

Spinal Adjustment/Manipulation:

Osseous Mechanisms

Part 1 of a 5 Part Series

By: Mark Studin

William J. Owens


Citation: Studin m., Owens W., (2017) The Mechanism of the Chiropractic Spinal Adjustment/Manipulation: Osseous Mechanisms, Part 1 of 5, American Chiropractor 39 (5), pgs. 30, 32, 34, 36-38


A report on the scientific literature



There have been many reports in the literature on chiropractic care and its efficacy. However, the reporting is often “muddled” based upon interchangeable terminology utilized to describe what we do. The etiology of the verbiage being used has apparently been part of a movement to gain acceptance within the healthcare community, but this attempt for a change in view by the healthcare community has cost us. Currently, the scientific community has lumped together manipulation performed by physical therapists or osteopaths with chiropractic spinal adjustments because all three professions perform “hands on” manual therapy to the spine. For example, Martínez-Segura, De-la-LLave-Rincón, Ortega-Santiago, Cleland, and Fernández-de-Las-Peñas (2012) discussed how physical therapists commonly use manual therapy interventions directed at the cervical or thoracic spine, and the effectiveness of cervical and thoracic spine thrust manipulation for the management of patients with mechanical, insidious neck pain. Herein lies the root of the confusion when “manipulation” is utilized as a “one-size-fits-all” category of treatment as different professions have different training and procedures to deliver the manipulation, usually applying different treatment methods and realizing different results and goals.

In addition, as discussed by Sung, Kang, and Pickar (2004), the terms “mobilization,” “manipulation” and “adjustment” also are used interchangeably when describing manual therapy to the spine. Some manipulation and virtually all chiropractic adjusting “…involves a high velocity thrust of small amplitude performed at the limit of available movement. However, mobilization involves repetitive passive movement of varying amplitudes at low velocity” (Sung, Kang, & Picker, 2004, p. 115).

To offset confusion between chiropractic and any other profession that involves the performance of some type of manipulation, for the purpose of clarity, we will be referring to any type of spinal therapy performed by a chiropractor as a chiropractic spinal adjustment (CSA) and reserve manipulation for other professions who have not been trained in the delivery of CSA. Until now, the literature has not directly supported the mechanism of the CSA. However, it has supported each component and the supporting literature, herein, will define the neuro-biomechanical process of the CSA and resultant changes. 

Components of the Adjustment or Thrust

Both human and animal studies have shown the tri-phasic process of the CSA and the time for the thrust duration of each phase.  In addition, the timing at each phase has been shown to be integral in understanding the neurological effect of the CSA. The forces are broken into 3 phases. These are the pre-load force, which takes the tissue close to its paraphysiological limit, the peak force or thrust stage and the resolution stage.


Pickar and Bolton (2012) reported the following:

CSA, referred to in the literature as spinal manual therapy, “…in the cervical region has relatively little pre-load ranging from 0 to 39.5 N. In contrast, the average pre-load forces during [CSA] in the thoracic region (139 ± 46 N, ± SD) and sacroiliac region (mean 88 N ± 78 N) are substantially higher than in the cervical region and are potentially different from each other. From the beginning of the thrust to end of the resolution phase, [CSA] duration varies between 90 and 120 ms. (mean = 102 ms.). The time to peak force during the thrust phase ranges from 30 to 65 ms. (mean = 48 ms.). Peak applied forces range from 99 to 140 N (mean = 118 N, n = 6 treatments). In the same study with [CSA] directed at the thoracic (T4) region and applied to three different patients by the same practitioner, the mean (SD) time to peak force was 150 ± 77 ms. and mean peak force reached 399 ± 119 N. During the resolution phase, force returned to pre-[CSA] levels over durations up to two times longer than that of the thrust phase. When [CSA] was applied to the sacroiliac joint, mean applied peak forces reached 328 ± 78 N, with the thrust and resolution phases having similar durations (∼100ms.). The peak force during manipulation of the lumbar spine measured by Triano and Schultz (1997) tended to be higher than during the thoracic or sacroiliac manipulation measured by Herzog et al. (1994) and the force–time profiles resembled half-sine waves with the time to and from peak taking approximately 200 ms. Peak impulse forces during thoracic manipulation approximated the >400 N peak impulse force measured by Triano and Schultz (1997). (p. 786)



Note. Spinal Manipulative Therapy and Somatosensory Activation,” by J. G. Pickar and P. S. Bolton, 2012, Journal of Electromyography and Kinesiology,22(5), 787. Copyright 2012 by Elsevier.


Pickar and Bolton (2012) reported that the physical characteristics of an CSA may vary based upon the technique being used and the individual practitioner. However, the above scenario is an illustration and guide to the time and force for of a CSA.




Zygapophysial (Z) joints

Cramer et al. (2002) explained the following:

One component of spinal dysfunction treated by chiropractors has been described as the development of adhesions in the zygapophysial (Z) joints after hypomobility. This hypomobility may be the result of injury, inactivity, or repetitive asymmetrical movements…one beneficial effect of spinal manipulation may be the “breaking up” of putative fibrous adhesions that develop in hypomobile or “fixed” Z joints. Spinal adjusting of the lumbar region is thought to separate or gap the articular surfaces of the Z joints. Theoretically, gapping breaks up adhesions, thus helping the motion segment reestablish a physiologic range of motion. (p. 2459)


Control subject [left] before the CSA and after [right] a CSA. The red arrows depict the increase in the Z-Joint

Note. The Effects of Side-Posture Positioning and Spinal Adjusting on the Lumbar Z Joints: A Randomized Controlled Trial with Sixty-Four Subjects,” by G. D.Cramer, D. M. Gregerson, J. T. Knudsen, B. B. Hubbard, L. M. Ustas, & J. A., 2002, Spine,27(22), 2462. Copyright 2002 by Lippincott Williams & Wilkins.


Cramer et al. (2002) found the following:

…significant differences between several groups in this study, with the group that received chiropractic adjustments and remained in the side-posture position showing the greatest increase in gapping. This finding is consistent with the hypothesis that chiropractic adjusting gaps the Z joints…The Z joints were found gap during side-posture positioning, although not as much as during side-posture adjusting…The flexion that occurs during the side-posture position and side-posture spinal adjustment may allow for greater gapping during axial rotation and may account for the difference in results between the studies. However, because both the side-posture positioning group and the group that had side-posture adjusting followed by continued side-posture positioning received equal amounts of flexion, the thrust given during the chiropractic procedure had the effect of increasing the gapping of the Z joints. (p. 2464)


The average difference between the control subjects…and the subjects that received a chiropractic adjustment and remained in side-posture position was 1.33 mm…a difference of 0.71 mm was found between the side-posture group…and the group that received an adjustment and remained in the side-posture position…It will be recalled that the Z joints are very small [and this is a considerable gap in a joint as small as the Z joint]…Another important consideration is that the term “residual,” or “left-over” gapping, could be applied to the gapping measured in the adjustment group because it can be logically assumed that the Z joints gap a greater distance during the forceful loading of the manipulative procedure than recorded in this study. The tissues of the spine presumably bring the articular surfaces back toward the pre-adjustment (closed) position as the patient resumes a more typical side-posture position after the thrust of a manipulation. This “residual” gapping is what was seen during the 15- to 20-minute MRI scan taken immediately after the adjustment. (2464-2565)


What makes this significant is the residual time that occurs after the CSA. During this period, and the time that follows is the foundation for biomechanical  changes in the adjacent discs and ancillary connective tissue attachments that will be discussed in the next article in the series. However, this is part of the foundation for bio-neuro-mechanical changes to the spine secondary to the CSA.



Meniscoid Entrapment


Evans (2002) reported the following:

…on flexion of the lumbar spine, the inferior articular process of a zygapophyseal joint moves upward, taking a meniscoid with it. On attempted extension, the inferior articular process returns toward its neutral position, but instead of re-entering the joint cavity, the meniscoid impacts against the edge of the articular cartilage and buckles, forming a space-occupying "lesion" under the capsule: a meniscoid entrapment. A large number of type III and type IV nerve fibers (nociceptors) have been observed within capsules of zygapophyseal joints. Pain occurs as distension of the joint capsule provides a sufficient stimulus for these nociceptors to depolarize. Muscle spasm would then occur to prevent impaction of the meniscoid. The patient would tend to be more comfortable with the spine maintained in a flexed position, because this will disengage the meniscoid. Extension would therefore tend to be inhibited. This condition has also been termed a "joint lock" or "facet-lock" the latter of which indicates the involvement of the zygapophyseal joint.


The presence of fibro-adipose meniscoids in the cervical zygapophyseal joints suggests that a similar phenomenon might occur, but in the neck the precipitating movement would be excessive rotation. The clinical features of cervical meniscoid entrapment would be those of an acute torticollis in which attempted derotation would cause impaction and buckling of the entrapped meniscoid and painful capsular strain. Muscle spasm would then occur to prevent impaction of the meniscoid by keeping the neck in a rotated position. Under these circumstances the muscle spasm would not be the primary cause of torticollis but a secondary reaction to the entrapment of the meniscoid.


An HVLAT manipulation, involving gapping of the zygapophyseal joint reduces the impaction and opens the joint, so encouraging the meniscoid lo return to its normal anatomical position in the joint cavity. This ceases the distension of the joint capsule, thus reducing pain.  (p. 252-253)

Evans (2002) also explained the following:


Zygapophyseal joint gapping induced during an HVLAT manipulation would further stretch the highly innervated joint capsule, leading to a "protective" reflex muscular contraction, as shown in electromyographic studies. The most important characteristic of a manipulative procedure that will provide joint gapping, before the induction of protective reflex muscular contraction, would be high velocity…the thrusting phase of an HVLAT manipulation required 91 ± 20 ms. to develop the peak force. If this period is compared with the time delay between the onset of the thrusting force and the onset of electromyographic activity, which ranges from 50 to 200 ms., we can see that a force of sufficient magnitude to gap the joint can be applied in a shorter time than that required for the initiation of a mechanoreceptor-mediated muscular reflex. Furthermore, once the muscle is activated (i.e. there is an electromyographic signal), it will take approximately another 40 to 100 ms until the onset of muscular force. It therefore seems unlikely that there are substantial muscular forces resisting the thrusting phase of HVLAT manipulation. Thus, HVLAT manipulation would again appear to be the treatment of choice for a meniscoid entrapment.


The cavitation event may not be a prerequisite for a "successful" HVLAT manipulation in the case of a meniscoid entrapment and may be an incidental side effect of high-velocity zygapophyseal joint gapping (which would be a prerequisite for success). Audible indication of successful joint gapping may, however, be regarded as desirable in itself as a clinical measure of "success." A clinician's perception of the occurrence of cavitation during an HVLAT manipulation has been shown to be very accurate and would therefore be a reliable measure of a '"successful" joint gapping. (p. 253-254)



Meniscoid entrapment. A) On flexion, the inferior articular process of a zygapophyseal joint moves upward, taking a meniscoid with It. B) On attempted extension, the inferior articular process returns upward to its neutral position, hut instead of re-entering the joint cavity, the meniscoid impacts against the edge of the articular cartilage and buckles, forming a space-occupying "lesion" under the capsule. Pain occurs as a result of capsular tension, and extension is inhibited. C) CSA (Manipulation) of the joint involving flexion and gapping, reduces the impaction and opens the joint to encourage re-entry of the meniscoid into the joint space (D) Realignment of the joint.


Note. Mechanisms and Effects of Spinal High-Velocity, Low-Amplitude Thrust Manipulation: Previous Theories,” by D. W. Evans, 2002, Journal of Manipulative and Physiological Therapeutics, 25(4), 253. Copyright 2002 by Elsevier.


This first part of a 5-part series covers the osseous mechanics of what the chiropractic spinal adjustment is comprised of. Part 2 will cover the ligamentous involvement from a supportive and neurological perspective. The topic of part 3 will be spinal biomechanics and its neurological components. Part 4 will be an in-depth contemporary comparative analysis of the chiropractic spinal adjustment vs. physical therapy joint mobilization. The final part will be a concise overview of the chiropractic spinal adjustment.




1. Martínez-Segura, R., De-la-LLave-Rincón, A. I., Ortega-Santiago, R., Cleland J. A., Fernández-de-Las-Peñas, C. (2012). Immediate changes in widespread pressure pain sensitivity, neck pain, and cervical range of motion after cervical or thoracic thrust manipulation in patients with bilateral chronic mechanical neck pain: A randomized clinical trial. Journal of Orthopedics & Sports Physical Therapy, 42(9), 806-814.

2. Sung, P. S., Kang, Y. M., & Pickar, J. G. (2004). Effect of spinal manipulation duration on low threshold mechanoreceptors in lumbar paraspinal muscles: A preliminary report. Spine, 30(1), 115-122.

3. Pickar, J. G., & Bolton, P. S. (2012). Spinal manipulative therapy and somatosensory activation.Journal of Electromyography and Kinesiology,22(5), 785-794.

4. Cramer, G. D., Gregerson, D. M., Knudsen, J. T., Hubbard, B. B., Ustas, L. M., & Cantu, J. A. (2002). The effects of side-posture positioning and spinal adjusting on the lumbar Z joints: A randomized controlled trial with sixty-four subjects.Spine,27(22), 2459-2466.

5. Cramer, G. D., Henderson, C. N., Little, J. W. Daley, C., & Grieve, T.J. (2010). Zygapophyseal joint adhesions after induced hypombility. Journal of Manipulative and Physiological Therapeutics, 33(7), 508-518.

6. Evans, D. W. (2002). Mechanisms and effects of spinal high-velocity, low-amplitude thrust manipulation: Previous theories. Journal of Manipulative and Physiological Therapeutics, 25(4), 251-262.

7. Owens, Jr., E. F., Hosek, R. S., Sullivan, S. G. B., Russell, B. S., Mullin, L. E., & Dever, L. L. (2016). Establishing force and speed training targets for lumbar spine high-velocity, low-amplitude chiropractic adjustments. The Journal of Chiropractic Education30(1), 7-13.

8. Nougarou, F., Dugas, C., Deslauriers, C., Pagé, I., & Descarreaux, M. (2013). Physiological responses to spinal manipulation therapy: Investigation of the relationship between electromyographic responses and peak force.Journal of Manipulative and Physiological Therapeutics,36(9), 557-563.

9. Solomonow, M. (2009). Ligaments: A source of musculoskeletal disorders.Journal of Bodywork and Movement Therapies,13(2), 136-154.

10. He, G., & Xinghua, Z. (2006). The numerical simulation of osteophyte formation on the edge of the vertebral body using quantitative bone re­modeling theory. Joint Bone Spine, 73(1), 95-101.

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Published in Neck Problems

Chiropractic vs. Physical Therapy

 in Treating Low Back Pain

with Spinal Adjustments vs. Exercise Rehabilitation



William J. Owens DC, DAAMLP

A report on the scientific literature


In the United Kingdom, Field and Newell (2016) reported that back pain accounts for 4.8% of all social benefit claims with overall costs reaching $7 billion pounds or $9.35 billion US dollars. Boyles (2016) reported that “Researchers from the University of Washington, Seattle, found that the nation's dramatic rise in expenditures for the diagnosis and treatment of back and neck problems has not led to expected improvements in patient health. Their study appears in the Feb. 13 issue of The Journal of the American Medical Association. After adjustment for inflation, total estimated medical costs associated with back and neck pain increased by 65% between 1997 and 2005, to about $86 billion a year… Yet during the same period, patients reported more disability from back and neck pain, including more depression and physical limitations.


“We did not observe improvements in health outcomes commensurate with the increasing costs over time," lead researcher Brook I. Martin, MPH, and colleagues wrote. "Spine problems may offer opportunities to reduce expenditures without associated worsening of clinical outcomes." ( Part of the explanation for the rise in cost of treatment of low back pain is the utilization of physical therapy by allopath’s (medical primary care providers and medical specialists) as the primary option for the treatment of low back pain vs. the literature verified better alternative of chiropractic based upon outcome studies.  


Through the years, both chiropractors and physical therapists have concurrently utilized exercise rehabilitation as a modality to treat low back pain. As a rule, the chiropractic profession has utilized exercise rehabilitation as an adjunct to the spinal adjustment where in physical therapy, it has been the main focus of the treatment plan. In addition, other passive modalities to mitigate pain, such as electrical stimulation and/or hydro/cryotherapy has been utilized as an adjunct to each professions main treatment. As a rule, exercise rehabilitation is a crucial adjunct to the treatment of low back disorders as it adds necessary motion to the joint and helps balance muscle tone required to create a biomechanically stabilized joint over time.

However, Ianuzzi and Khalsa (2005) wrote (pg. 674)


Facet joint capsule strain magnitudes during simulated high velocity low amplitude spinal manipulations were within the range of motion occurred during maximum physiological motions, indicating that the procedure is biomechanically safe and provide a stimulus that is likely sufficient to stimulate facet joint capsule neurons. However, physiological motions of the lumbar spine by themselves (e.g. Exercise) are generally ineffective in treating low back pain, suggesting that facet joint capsule strain magnitude alone would be insufficient in providing a novel stimulus for facet joint capsule afferents.


The high strain rates that occurred during spinal manipulation could provide a novel “yet biomechanically safe” stimulus for afferents innervating given facet joint capsule. Alternatively, during spinal manipulation, the relative magnitudes (patterns) of facet joint capsule strain was in a region of the lumbar spine may be unique, which could result in a novel pattern of facet joint capsule mechanoreceptor firing in the spinal region and subsequently a novel stimulus to the central nervous system.


Simply put, the facet joint capsules are comprised of ligaments where the mechanoreceptors are located. A spinal manipulation (chiropractic spinal adjustment) stimulates the neurons in the capsule where exercise (physiological motion) does not. In addition, it has been shown that chiropractic spinal adjustments are safe to the joint capsule and ligaments that comprise the capsule.




  1. Field J., Newell D. (2016) Clinical Outcomes In a Large Cohort of Musculoskeletal Patients Undergoing Chiropractic Care In the United Kingdom: A Comparison of Self and National Health Service Referral Routes, Journal of Manipulative and Physiological Therapeutics, 39(1), pgs. 54-62
  2. Boyles S., $86 Billion Spent on Back, Neck Pain, WebMD (2016) Retrieved from:
  3. Ianuzzi A., Khalsa P. (2005) High Loading Rate During Spinal Manipulation Produces Unique Facet Joint Capsule Strain Patterns Compared With Axial Rotations, Journal of Manipulative and Physiological Therapeutics 28 (9), 673-687

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Published in Low Back Problems

Chiropractic Spinal Adjustments,

 Changes in Organ Systems

& Treatment of Disease


A literature review and report on the positive effects of chiropractic on the autonomic nervous system, heart function and the circulatory system


A report on the scientific literature 


William Owens DC, DAAMLP


Citation: Studin M., Owens W., (2015) Chiropractic Spinal Adjustments, Changes in Organ Systems and Treatment of Disease, The American Chiropractor, 38(11) 20, 22-25


A report on the scientific literature 

The autonomic nervous system is the part of the nervous system that supplies the internal organs, including the blood vessels, stomach, intestine, liver, kidneys, bladder, genitals, lungs, pupils, heart, and sweat, salivary, and digestive glands.


The autonomic nervous system has two main divisions:

  • Sympathetic
  • Parasympathetic

After the autonomic nervous system receives information about the body and external environment, it responds by stimulating body processes, usually through the sympathetic division, or inhibiting them, primarily through the parasympathetic division. The autonomic nerve pathway involves two nerve cells. One cell is located in the brain stem or spinal cord and is connected by nerve fibers to the other cell, which is located in a cluster of nerve cells (called an autonomic ganglion). Nerve fibers from these ganglia connect with internal organs. Most of the ganglia for the sympathetic division are located just outside the spinal cord on both sides of it. The ganglia for the parasympathetic division are located near or in the organs they connect with.


The autonomic nervous system controls many internal body processes such as the following:

  • Blood pressure
  • Heart and breathing rates
  • Body temperature
  • Digestion
  • Metabolism (thus affecting body weight)
  • The balance of water and electrolytes (such as sodium and calcium)
  • The production of body fluids (saliva, sweat, and tears)
  • Urination
  • Defecation
  • Sexual response

Many organs are controlled primarily by either the sympathetic or the parasympathetic division. Sometimes the two divisions have opposite effects on the same organ. For example, the sympathetic division increases blood pressure, and the parasympathetic division decreases it. Overall, the two divisions work together to ensure that the body responds appropriately to different situations. (Low, 2015,


As you can see by the above definition, the human body is in large part controlled by autonomic or automatic nerves, the kind that function without your control. The question that has arisen throughout the years in chiropractic is, “Can the chiropractic spinal adjustment have an effect on those nerves and with that, can disease process or pathology be influenced? The question of the chiropractic spinal adjustment positively effecting pain through the brain connection (central nervous system) has already been conclusively established.


As reported these authors in 2015, the chiropractic adjustment produces direct and measureable effects on the central nervous system across multiple regions which is responsible for the processing of emotion (cingulate cortex, aka limbic cortex) and the insular cortex, which is also responsible for regulating emotion as well as homeostasis. The motor cortex is involved in the planning and execution of voluntary movements, the amygdala’s primary function is memory and decision making (also part of the limbic system), the somatosensory cortex is involved in processing the sense of touch (remember the homunculus) and, finally, the periaqueductal gray is responsible for descending pain modulation (the brain regulating the processing of painful stimuli).


The next question then becomes, “Can the chiropractic adjustment cause the central nervous system to effectuate changes in those systems that regulate our organs through the autonomic nervous system?” When studying the autonomic nervous system, according to Welch and Boone (2008), “Because of the proximity of the upper cervical vertebrae to the brainstem, parasympathetic influences dominate these segmental levels; and therefore, a cervical adjustment could likely result in a parasympathetic response (slowing down of heart beat, lowering of BP, constriction of pupils). In those spinal regions where sympathetic innervation is substantial (upper thoracic and upper lumbar), a chiropractic adjustment could elicit a sympathetic response (stimulation of heart beat, raising of BP, dilation of pupils” (p. 87).

In this study, the findings after a cervical adjustment were linked to an increase in parasympathetic dominance. This was apparent when observing the changes occurring in pre- to post-adjustment HRV [heart rate variability] total power that reflects the balance between LF [low frequency] (ie, sympathetic tone) and HF [high frequency] (e, parasympathetic tone). It was evident that, in each patient, the pre- to post-adjustment decrease in LF/HF [low frequency/high frequency] was due to either a larger increase in parasympathetic activity or a lesser decrease in parasympathetic activity when compared with sympathetic activity. These findings are consistent with other studies that have linked upper cervical chiropractic adjustments to parasympathetic mediated regulatory systems.

Among those individuals receiving thoracic adjustments, the findings indicated that the responses were sympathetic in nature…Heart rate variability data revealed that total power, which is a measure of total autonomic signal, decreased substantially post-adjustment. When considering the balance between parasympathetic/sympathetic activity (LH/HF) [low frequency/ high frequency], it was evident that, in each patient, the pre- to post-adjustment decrease in LH/HF [low frequency/high frequency] was due to either a larger increase in sympathetic activity or a lesser decrease in sympathetic activity when compared with parasympathetic activity. These findings are consistent with other studies that have linked thoracic chiropractic adjustments to sympathetic mediated regulatory systems.” (p. 90-91).

Budgell and Hirano (2001) reported, “…authentic spinal manipulation was associated with changes in heart rate and heart-rate variability, which could not be duplicated with sham manipulation. The distinguishing features of the authentic manipulation are the high-velocity, low-amplitude thrust applied to and resulting in cavitation of an intervertebral joint. The authentic manipulative procedure employed in this study has been widely used in clinical trials of the effects of spinal manipulation on headache and biomechanical disorders of the neck” (p. 98).


Budgell and Polus reported in The Journal of Manipulative and Physiological Therapeutics (2006) that chiropractic adjustments of the thoracic spine were associated with significant heart rate values and influenced the autonomic output of the heart, meaning that the heart rate generally lowers with the chiropractic adjustment because of the shift in the neurological communication of the autonomic nervous system (to the parasympathetic nerves) causing the heart to slow or normalize. This study by Budgell and Polus offers potential answers to many as to why patients' heart rates spike for no apparent reason. The spine, although a great influence to the nervous system, has often been overlooked in the clinical arena as the prime cause for cardiac issues. The authors of this article want to emphasize that chiropractic care has a positive effect for many conditions, including cardiac, and should be consideredin conjunction with necessary treatment from all other health care specialists, as clinically indicated, in order to make a conclusive diagnosis to rule out life-threatening illnesses.


Ward, Coats, Tyer, Weigand, and Williams (2013), found that in an upper thoracic manipulation (mobilization) of the thoracic spine, “There was no statistically significant or clinically relevant difference found between groups for any of the cardiovascular measurements at any time point” (p. 107). This study would appear to overturn the previous findings of autonomic change as a sequella to a chiropractic adjustment. However, if you look carefully at the study limitations, you will realize that this study strongly suggests that chiropractic has perhaps the “only solution” to effect autonomic changes. 


Ward et al. (2013) included the following points under the heading “Study Limitations.” “The population that we sampled was composed of chiropractic students who regularly receive spinal manipulation. It is possible that the general public who do not receive regular chiropractic manipulation may react differently than individuals who receive spinal manipulation more frequently. In our design, we did not attempt to exclusively manipulate fixated segments of the upper thoracic spine. It may be argued that, if a patient had a painful fixated spinal segment that was manipulated, the results of this study may have been different…Last, our study participants were young and relatively normotensive” (p. 108-109).


The limitations also suggest that the treatment rendered was a joint mobilization, similar to what physical therapy is designed to do and not a chiropractic spinal adjustment. There were no fixations, and a as result, no negative neurological sequelae. In addition, this study was performed on young, healthy chiropractic students who have been getting chiropractic adjustments on a regular basis, probably removing any aberrant neurological issues prior to this study. It is highly unlikely there were significant biomechanical alterations in this study population again, due to age and frequency of chiropractic care. 




Additionally, the lead author of this article, over the course of 5 years in private practice, did pre- and post-extremity Doppler studies on a “sick” population that was not receiving any chiropractic care and observed the same results as Welch and Boone stated above. In addition, Ward et al. (2013) appear to have validated why a chiropractic adjustment on a historical “chiropractic subluxated” region must be “adjusted chiropractically” to have the benefit of autonomic changes. It is the chiropractic “diagnosis” of the functional spinal biomechanical abnormality that is the expertise of the doctor of chiropractic, not simply the act of the therapeutic adjustment to treat neuromuscular negatively affected regions and not simply mobilize segments. 


Chronic pain patients were studied by Kang, Chen, Chen and Jaw (2012). Their focus was on the following: sleep disorders, pain scales, pressure pain thresholds, disability indexes and heart rate variability analysis. Although these authors have touched on many areas that have been reported to have a positive influence by chiropractic care, for the purpose of this review we are focusing on heart rate variability. Kang et al. (2012) reported, “Heart rate variability (HRV) analysis, initially developed to evaluate the prognosis of cardiac diseases, has been utilized to assess autonomic functions in chronic pain conditions…The autonomic nervous system plays an important role in the pathogenesis of chronic muscle pain. The autonomic dysfunction in fibromyalgia is characterized by persistent autonomic hyperactivity at rest and hypo-reactivity during stress. In addition, HRV analysis in patients with chronic low back pain has shown that a greater level of disability is associated with a lower HRV” (p. 797). They continued, “Our results are similar to a previous study demonstrating that in participants with chronic low back pain, decreased HRV is significantly associated with a higher index of perceived disability but not with pain intensity itself…It has long been postulated that autonomic regulatory dysfunction is involved in the pathogenesis of several chronic pain conditions” (Kang et al., 2012, p. 801). They concluded, “…reduced HRV was associated with subjective disability in patients with chronic neck pain” (Kang et al., 2012, p. 802).


Kang et al. (2012) stated, “The pathologic mechanism of chronic neck pain is still not understood and is a multifactorial disease… Chronic neck pain is difficult to treat. Treatment options must include multimodal, interventions combining physical agents, oral medications, local injections, and adequate exercise” (p. 800). This prevailing message perpetuates previous reports in the literature and further solidifies that allopathy has no solutions for mechanical cervical spine chronic pain. Apkarian ET. Al. (2004) reported that “Ten percent of adults suffer from severe chronic pain. Back problems constitute 25% of all disabling occupational injuries and are the fifth most common reason for visits to the clinic; in 85% of such conditions, no definitive diagnosis can be made.” (pg. 10410) Apkarian, Hashmi, and Baliki (2011) reported “Clinically, the most relevant conditions in which human brain imaging can have a substantial impact are chronic conditions, as they remain most poorly understood and minimally treatable by existing [medical] therapies” (p. S53).” In essence, what these authors are stating is that although many people suffer from chronic spine pain, very few of them are actually diagnosed with a “medical condition,” aka an “anatomical” lesion.  The chiropractic profession has long professed the lesion is actually functional and based on aberrant spinal biomechanics (subluxation) or mechanical spine pain (no fracture, tumor or infection). That, in fact, is what places chiropractic in the unique role in the diagnosis and management of biomechanical spine pain.  When we lead with “chiropractic spinal assessment,” we have no competition in medicine or rehabilitation.



Peterson, Bolton, and Humphreys (2012) “…investigate[d] outcomes and prognostic factors in patients with acute or chronic low back pain (LBP) undergoing chiropractic treatment” (p. 525). In chronic LBP, recent studies indicate that significant improvement is often fairly rapid, usually by the fourth visit, and that patients initially receiving treatment 3 to 4 times a week have better outcomes” (Peterson et al., 2012, p. 526). “Patients with chronic and acute back pain both reported good outcomes, and most patients with radiculopathy (neurogenic) also improved” (Peterson et al., 2012, p. 525). “At 3 months…69% of patients with chronic pain stated that they were either much better or better” (Peterson et al., 2012, p. 538). This is unlikely to be due to the natural history of low back pain because these patients have already passed the period when natural history occurs.



A study by Tamcan et al. (2010) was the only population-based study of the so called “natural history” of lower back pain and the authors found the “natural history” of chronic lower back pain was not ending in resolution of symptoms, but instead they documented patients moving “in and out” of a level of pain they could tolerate.   Based on the only population-based study of chronic lower back pain, the idea that the natural history of lower back pain ends with a resolution of symptoms is completely false and something that is merely perpetuated by our present healthcare system.

Lawrence et al. (2008) reported, “Existing research evidence regarding the usefulness of spinal adjusting… indicates the following…1. As much or more evidence exists for the use of SMT [spinal manipulation] to reduce symptoms and improve function in patients with chronic LBP as for use in acute and subacute LBP” (p. 670). “…the manual therapy group showed significantly greater improvements than did the exercise group for all outcomes. Results were consistent for both the short-term and the long-term” (Lawrence et al., 2008, p. 663). We see in this study, as in others, that biomechanical alterations in the human spine, aka spinal subluxation, must be diagnosed and treated. They cannot simply be exercised or mobilized away.  This is the unique domain of the doctor of chiropractic. 


Dunn, Green, Formolo, and Chicoine  (2011) reported, “The clinical outcomes achieved for this sample should be considered within the context of this veteran patient base, which is typically represented by older, white males with multiple comorbidities. A high percentage of overall service-connected disability was noted, with only a small percentage associated with the low back region. Considerable psychological comorbidity was found, with a high prevalence of PTSD [post-traumatic stress disorder] and depression diagnoses. PTSD and chronic pain tend to co-occur and may interact in a way that can negatively affect either disorder. A previous retrospective study of chiropractic management for neck and back pain demonstrated less improvement among those with PTSD. These points are significant because severe comorbidities and psychosocial factors lessen the likelihood of obtaining positive outcomes with conservative measures, including SMT [chiropractic adjustments], for chronic LBP [low back pain]. Mean percentages of clinical improvement exceeded the MCID [minimum clinically important difference], despite the levels of service-connected disability and comorbidity among this sample of veteran patients” (pg. 930). They went on to conclude that in spite of significant comorbidities that historically compromise positive results, 60.2% of patients met or exceeded the minimum clinically important difference for improvement.


The above studies verify that allopathy cannot conclude an accurate diagnosis for chronic back or neck pain while chiropractic reportedly helps resolve these issues 69% of the time as reported in the literature. The authors of this paper have currently practiced for a combined 52 years and can confirm, based upon our observations in the private practice setting, that the percentage is closer to 95% for resolving mechanical spine pain. Although this is an observation and could appear unusually high, that is an accurate accounting of both our experience and that of many other practicing chiropractors who we have informally polled. 


Therefore, the above studies, excluding Ward et al. (2013), strongly, suggest that the autonomic nervous system has a direct cause and effect relationship with the chiropractic spinal adjustment and verifies another central nervous system connection. They also verify that chiropractic has demonstrated solutions in today’s healthcare system that can help prevent autonomic aberrant effects of chronic pain on heart rate variability and other related disabilities where allopathy has failed.  


When we consider disease care, it is critical to consider the autonomic connection and the effect of chiropractic care as that is part of the equation for scientifically validating many observational conclusions that doctors of chiropractic have realized in their offices over the last century. In addition, this and other central nervous system connection show promising results as the foundation for determining how organs and disease react to the chiropractic spinal adjustment. Although the literature does confirm this hypothesis, it is based on millions getting well observationally and science simply needed time to catch up. Although we now are beginning to realize many answers there is still quite a way to go in our understanding… but we are just that much closer with understating more of the adjustment-central nervous system-autonomic nervous system-disease connection.




1. Low, P. (2015). Overview of the autonomic nervous system. Merck Manual Consumer Version, Retrieved from

2. Studin, M., & Owens W. (2015). Research proves chiropractic adjustments effect emotions, learning, memory, consciousness, motivation, homeostasis, perception, motor control, self-awareness, cognitive function, voluntary movement, decision making, touch and pain: BRAIN CONNECTION. US Chiropractic Directory. Retrieved from,-learning,-memory,-consciousness,-motivation,-homeostasis,-perception,-motor-control,-self-awareness,-cognitive-function,-voluntary-movement,-decision-making,-touch-and-pain.html

3. Welch, A., & Boone, R. (2008). Sympathetic and parasympathetic responses to specific diversified adjustments to chiropractic vertebral subluxations of the cervical and thoracic spine. Journal of Chiropractic Medicine, 7(3), 86-93.

4. Budgell, B., & Hirano, F. (2001). Innocuous mechanical stimulation of the neck and alteration in heart-rate variability in healthy young adults. Autonomic Neuroscience: Basic and Clinical 91(1-2), 96-99.

5. Budgell, B., & Polus, B. (2006). The effects of thoracic manipulation on heart rate variability: A controlled crossover trial.Journal of Manipulative and Physiological Therapeutics, 29(8), 603-610.

6. Ward, J., Coats J., Tyer, K., Weigand, S., Williams, G. (2013). Immediate effects of anterior upper thoracic spine manipulation on cardiovascular response. Journal of Manipulative and Physiological Therapeutics, 36(2), 101-110.

7 Kang, J. H., Chen, H. S., Chen, S. C., & Jaw, F. S. (2012). Disability in patients with chronic neck pain, Heart rate variability analysis and cluster analysis. Clinical Journal of Pain, 28(9), 797-803.

8. Apkarian V., Sosa Y., Sonty S., Levy R., Harden N., Parrish T., Gitelman D., (2004) Chronic Back Pain Is Associated with Decreased Prefrontal and Thalamic Gray Matter Density, The Journal of Neuroscience, 24(46) 10410-10415

Apkarian, A. V., Hashmi, J. A., & Baliki, M. N. (2011). Pain and the brain: Specificity and plasticity of the brain in clinical chronic pain. Pain, 152(Suppl. 3), S49-S64.

9. Peterson, C. K., Bolton, J., & Humphreys, B. K. (2012). Predictors of improvement in patients with acute and chronic low back pain undergoing chiropractic treatment. Journal of Manipulative and Physiological Therapeutics, 35(7) 525-533.

10. Tamcan, O., Mannion, A. F., Eisenring, C., Horisberger, B., Elfering, A., & Müller, U. (2010). The course of chronic and recurrent low back pain in the general population. Pain, 150(3), 451-457.

11. Lawrence, D. J., Meeker, W., Branson, R., Bronford, G., Cates, J. R., Haas, M., Hawk, C. (2008). Chiropractic management of low back pain and low back-related leg complaints: A literature synthesis. Journal of Manipulative and Physiological Therapeutics, 31(9), 659-674.

12.  Dunn, A. S., Green, B. N., Formolo, L. R., & Chicoine, D. (2011). Retrospective case series of clinical outcomes associated with chiropractic management for veterans with low back pain. Journal of Rehabilitation Research & Development, 48(8), 927-934.


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Published in Neck Problems

Case Report


By: Karen M. Callaghan, DC

Title: Spinal Adjustments are Safe in the Presence of Herniated disc with the Absence of Cord Compression

Abstract: The objective was to explore the use of MRI to increase the efficacy and safeness of adjusting the cervical spine in the presence of a disc herniation when there is no evidence of cord compression on MRI.

Key Words: Chiropractic, spinal adjustment, MRI, herniation

Introduction:  A 30 year old male patient presented to the office on 1/8/14 with injuries from a motor vehicle accident.  The motor vehicle accident had occurred 3 weeks prior to his first visit.  The patient was the restrained front seat passenger.  The car he was travelling in struck another car and the patient’s car was flipped over onto its roof.  While the car remained on its roof the patient was able to crawl out and awaited medical attention.  The patient was taken by ambulance to the hospital where he was examined and testing was ordered.  The patient had multiple CT scans of the head and X-rays of the cervical and lumbar.  The CT of the head revealed a nasal fracture and the patient underwent immediate surgery to repair his broken nose. 

The patient presented three weeks post-accident with persistent and progressive daily occipital headaches, neck pain into the shoulders bilaterally, upper back pain and lower back pain that radiates into the legs and down into the feet bilaterally. He has swelling at the left anterior knee and bandages around the right elbow and two black eyes. 

The patient states that he was having difficulty with regular activities of daily living including walking for more than 15-20 minutes, long periods of standing, more than an hour of sitting, any bending or lifting and any regular daily chores.  The patient also states he was having difficulty getting a restful night’s sleep due to the pain.  The patient’s visual analog scale rating was 10 out of 10.

History: The patient denied any prior history of neck or back pain.  No reported prior injuries or traumas.

Objective Findings:  An examination was performed and revealed the following:

            Range of Motion: 

Cervical Motion Studies:

Flexion: Normal=60                      Exam-   25 with pain  with spasm 

Extension: Normal=50                  Exam-   20 with pain  with spasm

Left Rotation: Normal=80             Exam-   35 with pain  with spasm

Right Rotation: Normal=80           Exam-   35 with pain  with spasm

Left Lat. Flex: Norma=-40             Exam-   15 with pain  with spasm

Right Lat. Flex: Normal=40           Exam-   15 with pain  with spasm


Dorsal-Lumbar Motion Studies:

Flexion: Normal=90                  Exam-   35 with pain   with spasm

Extension: Normal=30              Exam-   10 with pain  with spasm 

Left Rotation: Normal=30         Exam-   10 with pain  with spasm

Right Rotation: Normal=30       Exam-   5 with pain  with spasm 

Left Lat. Flex: Normal=20         Exam-   5 with pain  with spasm 

Right Lat. Flex: Normal=20       Exam-   5 with pain  with spasm 



Orthopedic Testing

The orthopedic testing revealed the following positive orthopedic tests in the cervical spine: Valsalva’s indicating the presence of a disc at L4-S1 and the lower cervical region, foraminal compression indicating radicular pain in the lower cervical region, Jackson’s compression , shoulder depressor and cervical distraction all indicating pain in the lower cervical region.  The lumbar testing revealed a positive Soto-Hall with pain at the L4-S1 level, Kemps positive with pain from L4-S1, Straight Leg raiser with pain at 60 degrees, Milgram’s with pain at the L5-S1 level, Lewin’s with pain at L5-S1, and Nachlas eliciting pain in the L5-S1 region.


Neurological Testing

The neurological exam revealed bilateral upper extremity tingling and numbness into the shoulder on the left and down the right arm into the hand. The lower extremity revealed tingling and numbness into the gluteal’s bilaterally with left sided radicular pain in to the leg into left foot.  The pinwheel revealed hypoesthesia at C7 bilaterally and L5 bilaterally dermatome level. The patient was unable to perform the heel-toe walk

The chiropractic motion palpation and static palpation exam revealed findings  at C 1,2 , 5, 6, 7 and T 2,3,4,9, 10  and L 3,4,5 as well as the sacrum.

X Ray  Studies:

The hospital had cervical x-rays and a CT of the head on the day of the accident. Thoracic and lumbar studies were needed as a result of the positive testing and the patients history and complaints The x-ray studies revealed a reversed cervical curve and misalignment of the C1,2,5,6,7 and the lumbar studies revealed a mild IVF encroachment at L5-S1 with rotations at L3,4,5.

The results of the exam were reviewed.  The patient’s positive orthopedic testing, neurological deficits coupled with the decreased range of motion and positive chiropractic motion and static palpation indicated the necessity to order both cervical[1]and lumbar[2]  MRI’s4.

 MRI results

The MRI images were personally reviewed.  The cervical MRI revealed a right paracentral disc herniation at the level of C5-6 with impingement on the anterior thecal sac.  There is also a C6-7 disc bulge impinging on the anterior thecal sac. The lumbar MRI revealed an L5-S1 disc herniation.  There are disc bulges at from L2-L4.

                  CERVICAL MRI STUDIES


Treatment Plan:

After reviewing the history, examination, prior testing, x-rays, MRI’s and DOBI care paths3 it was determined that chiropractic adjustments6  wereclinically indicated

The patient was placed on a treatment plan of spinal manipulation with modalities including intersegmental traction, electric muscle stimulation and moist heat.  Diversified technique was used to adjust the subluxation diagnosed levels of C1,2,5,6,7 and L3,4,5.  Although there were herniated and bulging discs present in the cervical and lumbar spine there was no cord compression. Therefore; there was no contraindication to performing a spinal adjustment.  As long as there is enough space between the cord and the herniation or bulge then it is generally safe to adjust.5

The patient responded quite favorably to the spinal adjustments and therapies over the course of 6 months of treatments.  Initially, the patient was seen three times a week for the first 90 days.  The patient demonstrated subjective and objective improvement and his care plan was adjusted accordingly and reduced to two visits per week for the next 90 days of care.  His range of motion returned to 90% of normal:

Range of Motion: 

Cervical Motion Studies:

Flexion: Normal=60                      Exam-   55 with no pain 

Extension: Normal=50                  Exam-   40 with mild tenderness

Left Rotation: Normal=80             Exam-   75 with mild tenderness

Right Rotation: Normal=80           Exam-   75 with mild tenderness

Left Lat. Flex: Norma=-40             Exam-   35 with no pain 

Right Lat. Flex: Normal=40           Exam-   35 with no pain


Dorsal-Lumbar Motion Studies:

Flexion: Normal=90                  Exam-   80 with tenderness

Extension: Normal=30              Exam-   25 with tenderness 

Left Rotation: Normal=30         Exam-   25 with no pain

Right Rotation: Normal=30       Exam-   25 with no pain

Left Lat. Flex: Normal=20         Exam-   20 with no pain 

Right Lat. Flex: Normal=20       Exam-   20 with no pain


The patient had decreased spasm, decreased pain, increased ability to perform ADL’s and his sleep had returned to normal. The patient states that he was no longer having the same difficulties with regular activities of daily living.  He was now able to walk for 45 minutes to 1 hour before the lower back pain flared up, he is able to stand for 1-2 hours before the lower back pain begins, he is able to sit for an hour or more before the lower back pain flares up. When the patient bends or lifts he has learned to use his core and lifts less than 20-30 pounds to avoid exacerbating his low back.  The patient also states he was no longer having difficulty getting a restful night’s sleep.  The patient’s visual analog scale rating was 3 out of 10.


The patient presented 3 weeks post trauma with cervical and lumbar pain as well as headaches.  The symptoms were progressing and the pain was radiating into the upper and lower extremities.  The history and exam indicated the presence of a herniated disc in the lower lumbar and cervical region.  Cervical and lumbar MRI’s were ordered to identify the presence of the herniated disc as well as to determine whether or not the patient should be adjusted.  The MRI results of both the cervical and lumbar MRI revealed herniated discs, however, because these discs were not causing cord compression it was safe to adjust the cervical and lumbar spine5.

Competing Interests:  There are no competing interests in the writing of this case report.


De-Identification: All of the patient’s data has been removed from this case.



  1. New England Journal of Medicine; Cervical MRI, July 28, 2005, Carette S. and Fehlings M.G.,N Engl J Med 2005; 353:392-399MRI for the lumbar disc, March 14  2013, el Barzouhi A., Vleggeert-Lankamp C.L.A.M., Lycklama à Nijeholt G.J., et al., N Engl J Med 2013; 368:999-1000 -16.7KB
  2. New England Journal of Medicine; Cervical-Disk HerniationN Engl J Med 1998; 339:852-853September 17, 1998DOI: 10.1056/NEJM199809173391219
  3. Is It Safe to Adjust the Cervical Spine in the Presence of a Herniated Disc? By Donald Murphy, DC, DACAN, Dynamic Chiropractic, June 12, 2000, Vol. 18, Issue 13
  4. Treatment Options for a Herniated Disc;  Spine-Health, Article written by:John P. Revord, MD

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Published in Case Reports

How Does the Chiropractic Adjustment Work?

A Literature Review of Pain Mechanisms & Brain Function Alteration

A report on the scientific literature 


William J. Owens DC, DAAMLP


Reference: Studin M., & Owens W., (2015) How Does the Chiropractic Adjustment Work? A Literature Review of Pain Mechanisms and Brain Function Alteration, The American Chiropractor 37(8)  30, 32-34, 36-38, 40, 42-43


Were D.D. and B.J. Palmer right with their bone on nerve theory?According to Charles A. Lantz, DC. PhD. Director of Research, Life Chiropractic College West (2015), Montgomery and Nelson cited the context within which medical authors in the mid- to late 19th century referred to subluxation, one that was similar to how D.D. Palmer later would:


A vertebra is said to be displaced or luxated when the joint surfaces are entirely separated. Sub-luxation is a partial or incomplete separation: one in which the articulating surfaces remain in partial contact. This latter condition is so often referred to and known by chiropractors as sub-luxation. The relationship existing between bones and nerves are so nicely adjusted that anyone of the 200 bones, more especially those of the vertebral column, cannot be displaced ever so little without impinging upon adjacent nerves. Pressure on nerves excites, agitates, creates an excess of molecular vibration, whose effects, when local, are known as inflammation, when general, as fever. A subluxation does not restrain or liberate vital energy. Vital energy is expressed in functional activity. A subluxation may impinge against nerves, the transmitting channel may increase or decrease the momentum of impulses, not energy. http://www.chiro. org/LINKS/FULL/A_Review_of_the_Evolution.shtml#Citation_7


Lance (2015) also reported, "According to BJ Palmer, a subluxation represented a displaced bone that impinged on a nerve, thus interfering with the transmission of vital nerve energy (or, more specifically, the transmission of ‘mental impulses.’)” ( Evolution. shtml)


For over a century, doctors of chiropractic have been explaining chiropractic by teaching patients and the medical community that there are bones compressing/irritating spinal nerves. The ensuing nervous system dysfunctions have negative effects on the function of peripheral nervous systems, central nervous systems and patients’ overall ability to maintain homeostasis. Essentially, they go into states of dis-ease.  These discussions were in large part due to the teachings of D.D. Palmer and B.J. Palmer as previously cited. Based on the results rendered in chiropractic offices across the country and in a patient-driven model of success, the general consensus in both private practice and chiropractic academia had been to maintain status quo and simply teach what has worked in the absence of conclusive evidence, particularly in light of a lack of serious governmental funding and support for chiropractic research.  In addition, dogma has also created blinders for many, as evidence evolves to further chiropractic and its understanding, application and expansion.


Over the last 10-15 years, research has been published by the scientific community that has begun to verify that D.D. and B.J. Palmer’s hypotheses were fundamentally correct, while clarifying the specific physiological mechanisms related to chiropractic’s ability to alleviate pain.  As a result of initially studying pain mechanisms, contemporary research has also begun to set the foundation for understanding why chiropractic works with systemic and autonomic dysfunction and potential disease treatment through the adjustment – central nervous system connection. It is the understanding of that connection with pain that is helping people to begin to understand the full impact of the chiropractic spinal adjustment and render the evidence to help more get well.




Coronado et al. (2012) reported that, “Reductions in pain sensitivity, or hypoalgesia, following SMT [spinal manipulative therapy or the chiropractic adjustment] may be indicative of a mechanism related to the modulation of afferent input or central nervous system processing of pain” (p. 752). “The authors theorized the observed effect related to modulation of pain primarily at the level of the spinal cord since (1) these changes were seen within lumbar innervated areas and not cervical innervated areas and (2) the findings were specific to a measure of pain sensitivity (temporal summation of pain), and not other measures of pain sensitivity, suggesting an effect related to attenuation of dorsal horn excitability and not a generalized change in pain sensitivity” (Coronado et al., 2012, p. 752). These findings indicate that a chiropractic spinal adjustment affects the dorsal horns at the root levels which are located in the central nervous system.  This is the beginning of the “big picture” since once we identify the mechanism by which we can positively influence the central nervous system, we can then study that process and its effects in much more depth.    


One of the main questions asked by Corando et al. (2012) “…was whether SMT (chiropractic adjustments) elicits a general response on pain sensitivity or whether the response is specific to the area where SMT is applied. For example, changes in pain sensitivity over the cervical facets following a cervical spine SMT would indicate a local and specific effect while changes in pain sensitivity in the lumbar facets following a cervical spine SMT would suggest a general effect. We observed a favorable change for increased PPT [pressure pain threshold] when measured at remote anatomical sites and a similar, but non-significant change at local anatomical sites. These findings lend support to a possible general effect of SMT beyond the effect expected at the local region of SMT application (p. 762).


The mechanisms of SMT are theorized to result from both spinal cord mediated mechanisms and supraspinal mediated mechanisms [brain]. A recent model of the mechanisms of manual therapy suggests changes in pain related to SMT result from an interaction of neurophysiological responses related to the peripheral nervous system and the central nervous system at the spinal and supraspinal level” (Coronado et al., 2012, p. 762).  This demonstrates that the chiropractic adjustment influences the peripheral nervous system and the central nervous system.  “Collectively, these studies provide evidence that SMT has an immediate effect on reducing pain sensitivity, most notably at the remote region of stimulus assessment with similar results in clinical and healthy populations” (Coronado et al., 2012, p. 763). 




Reed, Pickar, Sozio, and Long (2014) reported:

…forms of manual therapy have been clinically shown to increase mechanical pressure pain thresholds (i.e., decrease sensitivity) in both symptomatic and asymptomatic subjects.Cervical spinal manipulation has been shown to result in unilateral as well as bilateral mechanical hypoalgesia. Compared with no manual therapy, oscillatory spinal manual therapy at T12 and L4 produced significantly higher paraspinal pain thresholds at T6, L1, and L3 in individuals with rheumatoid arthritis. The immediate and widespread hypoalgesia associated with manual therapy treatments has been attributed to alterations in peripheral and/or central pain processing including activation of descending pain inhibitory systems.

Increasing evidence from animal models suggests that manual therapy activates the central nervous system and, in so doing, affects areas well beyond those being treated. (p. 277)

Reed et al. (2014) also reported:


The finding that only the higher intensity manipulative stimulus (ie, 85% BW [body weight] vs 55% BW or control) decreased the mechanical sensitivity of lateral thalamic neurons to mechanical trunk stimulation coincides with other reports relating graded mechanical or electrical stimulus intensity to the magnitude of central inhibition…

Several clinical studies indicate that spinal manipulation [chiropractic spinal adjustment] alters central processing of mechanical stimuli evidenced by increased pressure pain thresholds and decreased pain sensitivity in asymptomatic and symptomatic subjects following manipulation. (p. 282)


Thalamus. (2015). Wikipedia. Retrieved from http://en.wikipedia.orgwiki/Thalamus

The thalamus has multiple functions. It may be thought of as a kind ofhubof information. It is generally believed to act as a relay between different subcortical areas and thecerebral cortex. In particular, every sensory system (with the exception of theolfactory system) includes a thalamic nucleus that receives sensory signals and sends them to the associated primary cortical area. For the visual system, for example, inputs from theretinaare sent to thelateral geniculate nucleusof the thalamus, which in turn projects to thevisual cortexin theoccipital lobe. The thalamus is believed to both process sensory information as well as relay it—each of the primary sensory relay areas receives strong feedback connections from the cerebral cortex. Similarly themedial geniculate nucleusacts as a keyauditoryrelay between theinferior colliculusof themidbrainand theprimary auditory cortex, and the ventral posterior nucleusis a keysomatosensoryrelay, which sends touch andproprioceptiveinformation to theprimary somatosensory cortex.


The thalamus also plays an important role in regulating states ofsleep and wakefulness.Thalamic nuclei have strong reciprocal connections with the cerebral cortex, formingthalamo-cortico-thalamic circuitsthat are believed to be involved withconsciousness. The thalamus plays a major role in regulating arousal, the level of awareness, and activity (“Thalamus,”


This indicates that the chiropractic spinal adjustment reduces pain by effecting the thalamus and descending central pain pathways, while mobilization does not show evidence of having the same effect.  In addition, with our current knowledge of the chiropractic adjustment effecting the thalamus, we can begin to offer an explanation of how the first historically reported chiropractic adjustment by D.D. Palmer helped Harvey Lilard regain his hearing. 



Mohammadian, Gonsalves, Tsai, Hummel, and Carpenter (2004) investigated “the hypoalgesic effects of a single SMT on acute inflammatory reactions and pain induced by capsaicin [hot pepper extract]. These effects were assessed by measuring both sensory (allodynia [central nervous system pain], hyperalgesia, spontaneous pain intensity) and local vascular parameters (blood flow)” (p. 382). They reported “As expected, topical capsaicin induced primary hyperalgesia in the application area and secondary hyperalgesia outside that area. While the local vascular parameter blood flow was not affected by a single SMT [spinal manual therapy], the results indicated that sensory parameters (spontaneous pain perception and areas of both secondary hyperalgesia and allodynia) were significantly altered after spinal manipulation compared with N-SMT [non-spinal manipulative therapy]. These results clearly demonstrated that in contrast to the N-SMT condition, a single spinal manipulation triggered hypoalgesic effects” (Mohammadian et al., 2004, p. 385).


“In the present study, local blood flow was not affected by a single SMT. However, significant changes were observed on sensory parameters, supporting the hypothesis of centrally mediated effects of a single SMT. It is well known that secondary hyperalgesia appears to be due to central sensitization of the spinal dorsal horn neurons,while primary hyperalgesia is caused by nociceptor sensitization. It has also been discussed that mechanisms underlying allodynia are centrally mediated.Our findings also confirm the view that the hypoalgesic effects of a single SMT might be due to central modulation. These effects could also be explained as a result of a stress reaction caused by spinal manipulation treatment…Other studies discussed thatspinal manipulation [chiropractic spinal adjustments] stimulates mechanoreceptors of the spinal joints, resulting in afferent discharges and subsequently causing inhibitory reactions on the dorsal horn neurons.Vicenzino et al. demonstrated also a strong correlation between hypoalgesic and sympathoexcitatory effects, suggesting that a central control mechanism might be activated by manipulative therapy… previous studies as well as the present investigation…indicate that hypoalgesic effects of spinal manipulation are more likely mediated through central modulation” (Mohammadian et al., 2004, p. 386).  This study suggests that the chiropractic spinal adjustment affects the nociceptors and the mechanoreceptors at the joint level causing central modulation of an effect at the cord and/or brain level(s) and pain reductions in multiple areas as a result.



Gay, Robinson, George, Perlstein, and Bishop (2014) reported, “With the evidence supporting efficacy of MT [manual therapy or chiropractic spinal adjustments] to reduce pain intensity and pain sensitivity, it is reasonable to assume that the underlying therapeutic effect of MT is likely to include a higher cortical component” (p. 615).   It is in this place in particular that chiropractic must lead in both clinical application and academic processes such as formal continuing education lectures and research.


In the study conducted by Gay et al. (2014), “…pain-free volunteers processed thermal stimuli applied to the hand before and after thoracic spinal manipulation (a form of MT).  What they found was that after thoracic manipulation, several brain regions demonstrated a reduction in peak BOLD [blood-oxygen-level–dependent] activity. Those regions included the cingulate, insular, motor, amygdala and somatosensory cortices, and the PAG [periaqueductal gray regions]” (p. 615). In other words, thoracic adjustments produced direct and measureable effects on the central nervous system across multiple regions, which in the case of the responsible for the processing of emotion (cingulate cortex, aka limbic cortex) are regarding the insular cortex which also responsible for regulating emotion as well has homeostasis. The motor cortex is involved in the planning and execution of voluntary movements, the amygdala’s primary function is memory and decision making (also part of the limbic system), the somatosensory cortex is involved in processing the sense of touch (remember the homunculus) and, finally, the periaqueductal gray is responsible for descending pain modulation (the brain regulating the processing of painful stimuli).


Brain Region


Cingulate Cortex

Emotions, learning, motivation, memory

Insular Cortex

Consciousness, homeostasis, perception, motor control, self-awareness, cognitive function

Motor Cortex

Voluntary movements

Amygdala Cortex

Memory, decision making, emotional reactions

Somatosensory Cortex

Proprio and mechano-reception, touch, temperature, pain of the skin, epithelial, skeletal muscle, bones, joints, internal organs and cardiovascular systems

Periaqueductal Gray

Ascending and descending spinothalamtic tracts carrying pain and temperature fibers


This is a major step in showing the global effects of the chiropractic adjustment, particularly those that have been observed clinically, but not reproduced in large studies.  “The purpose of this study was to investigate the changes in FC [functional changes] between brain regions that process and modulate the pain experience after MT [manual therapy]. The primary outcome was to measure the immediate change in FC  across brain regions involved in processing and modulating the pain experience and identify if there were reductions in experimentally induced myalgia and changes in local and remote pressure pain sensitivity” (Gay et al., 2014, p. 615).  Simply put, can the processing of pain be modulated or regulated from an external force without the use of pharmacy or surgery? 


“Within the brain, the pain experience is subserved by an extended network of brain regions including the thalamus (THA), primary and secondary somatosensory, cingulate, and insular cortices.Collectively, these regions are referred to as the pain processing network (PPN) and encode the sensory discriminate and cognitive and emotional components of the pain experience.Perception of pain is dependent not merely on the neural activity within the PPN [pain processing network] but also on the flexible interactions of this network with other functional systems, including the descending pain modulatory system” (Gay et al., 2014, p. 617).  This is part of the reason why some patients experience pain differently than others.  Some have anxiety, depression and are at a loss to function while others can “ignore” the pain and maintain an adequate functional level as a productive member of society.  Pain is deeply tied to the most primitive regions of the central nervous system and it appears (as chiropractors have observed clinically for 116 years) that therapeutically speaking, we can have an influence on these higher centers with little or no side-effects.   


Gay et al. (2014) went on to report, “This study assessed the relationship of brain activity between regions of the PPN [pain processing network] before and after MT [manual therapy or chiropractic spinal adjustments]. Using this approach, we found common and treatment-dependent changes in FC [functional changes]…Our study is unique in our neurophysiologic measure because we used resting-state fMRI [functional MRI] in conjunction with FC [functional change] analyses. Our results are in agreement with studies that have found immediate changes using other neurophysiologic outcomes, such as Hoffman-reflex and motor-neuron excitability, electroencephalography with somatosensory-evoked potentials, transcranial magnetic stimulation with motor evoked potentials, and task-based fMRI with peak BOLD response” (p. 619 and 624).  This study concludes that chiropractic spinal adjustments create functional changes in multiple regions of the brain based upon multiple outcome measures.   In the study by Gay et al. 2014), this was measureable and reproducible. In addition, this has far reaching effects in setting the foundation for understanding how the adjustment works in systemic and possibly autonomic changes by being able to measure and reproduce functional changes within the brain as direct sequellae.




Daligadu, Haavik, Yielder, Baarbe, and Murphy (2013) also reported that “Numerous studies indicate that significant cortical plastic changes are present in various musculoskeletal pain syndromes.In particular, altered feed-forward postural adjustments have been demonstrated in a variety of musculoskeletal conditions including anterior knee pain, low back pain,and idiopathic neck pain.Furthermore, alterations in trunk muscle recruitment patterns have been observed in patients with mechanical low back pain” (p. 527). What this means is that there are observable changes in the function of the central nervous system seen in patients with musculoskeletal conditions.  That is something that chiropractors have observed clinically and shows the medical necessity for chiropractic care for both short and long term management as well as in the prevention of pain syndromes. 


Daligadu et al. (2013) stated the following:


There is also evidence in the literature to suggest that muscle impairment occurs early in the history of onset of spinal complaints,and that such muscle impairment does not automatically resolve even when pain symptoms improve. This has led some authors to suggest that the deficits in proprioception and motor control, rather than the pain itself, may be the main factors defining the clinical picture and chronicity of various chronic pain conditions.

Furthermore, recent evidence has demonstrated that spinal manipulation can alter neuromuscular and proprioceptive function in patients with neck and back pain as well as in asymptomatic participants. For instance, cervical spine manipulation has been shown to produce greater changes in pressure pain threshold in lateral epicondylalgia than thoracic manipulation; and in asymptomatic patients, lumbar spine manipulation was found to significantly influence corticospinal and spinal reflex excitability. “Interestingly, Soon et al did not find neurophysiological changes following mobilization on motor function and pressure pain threshold in asymptomatic individuals, perhaps suggesting that manipulation [chiropractic spinal adjustments], as distinct from mobilization, induces unique physiological changes. There is also accumulating evidence to suggest that chiropractic manipulation can result in changes to central nervous system function including reflex excitability, cognitive processing, sensory processing, and motor output.There is also evidence in SCNP [sub-clinical neck pain] individuals that chiropractic manipulation alters cortical somatosensory processingand elbow joint position sense.This evidence suggests that chiropractic manipulation may have a positive neuromodulatory effect on the central nervous system, and this may play a role in the effect it has in the treatment of neck pain. It is hoped improving our understanding of the neurophysiological mechanisms that may precede the development of chronic neck pain in individuals with SCNP will help provide a neurophysiological marker of altered sensory processing that could help determine if an individual is showing evidence of disordered sensorimotor integration and thus might benefit from early intervention to prevent the progression of SCNP into more long-term pain states.  (p. 528)


The authors went on to state, “Previous work using paired-pulse transcranial magnetic stimulation (TMS) of the motor cortex has indicated that cervical spine manipulation can alter sensorimotor integration of the upper limb by decreasing the amount of short-interval intracortical inhibition (SICI).A recent somatosensory evoked potential (SEP) study involving dual SEPs from the median and ulnar nerves demonstrated that cervical manipulation of dysfunctional areas in patients with a history of reoccurring neck pain or stiffness was able to affect sensorimotor integration…spinal manipulation altered the way the central nervous system responded to the motor training task” (Daligadu et al., 2013, p. 528).


Furthermore, the authors added, “…altered afferent input from the neck due to joint dysfunction leads to disordered sensorimotor integration within the cerebellum and a subsequent derangement in motor commands to the upper limb. The cerebellum plays a fundamental role in detecting the encoded afferent signal and relaying this information as part of the body schema. When the input signal is no longer encoded as a result of joint dysfunction and altered afferent input, the cerebellum must adjust to new encodings that dictate the body schema and affect proper execution of the motor task” (p. 529).


“Motor sequence learning tasks have been previously shown to induce plasticity within the circuitry of both the motor cortexand the cerebellum…Neck manipulation [chiropractic spinal adjustments] has also been shown to provide a modulatory effect on the motor cortex by reducing the amount of intracortical inhibition.” (Daligadu et al., 2013, p. 533).


“This study further adds to the literature by demonstrating an alteration in cerebellar modulation of motor output in SCNP [sub-clinical neck pain] patients when they received a manipulation-based chiropractic treatment before performing motor sequence learning.In the healthy control group, there was no change in CBI seen following motor sequence learning alone” (Daligadu et al., 2013, p. 534).


“If the motor sequence learning task had a significant effect on the cerebellum in this group of participants due to their neck pain and altered sensorimotor integration, then it is possible that a decreased level of CBI [cerebellar inhibition] output to the motor cortex would result in an increase in SICI [short-intracortical inhibition]” (Daligadu et al., 2013, p. 534). The significance of this study is that it suggests that the chiropractic spinal adjustment improves not just neck dysfunction, but through plasty changes in the cerebellum, there is resultant motor learning and increased function. 




Based upon the scientific evidence, chiropractic spinal adjustments stimulate mechanoreceptors and nociceptors of the spinal joints resulting in afferent discharges and subsequently causing central modulation with an effect at the cord and brain levels. This causes pain reductions and secondary hyperalgesia (pain reduction in remote regions) which appears to be due to central sensitization of the spinal dorsal horn neurons,while primary hyperalgesia is caused by nociceptor sensitization.


This verifies that chiropractic adjustments influence the peripheral nervous system and the central nervous system. In the central nervous system, chiropractic spinal adjustments reduce pain by effecting the thalamus and descending central pain pathways.


Chiropractic spinal adjustments also create functional changes in multiple regions of the brain based upon multiple outcome measures that are measureable and reproducible. The areas of the brain affected by chiropractic adjustments effect the following functions: emotions, learning, motivation, memory, consciousness, homeostasis, perception, motor control, self-awareness, cognitive function, voluntary movements, decision making, touch, temperature, pain of the skin- epithelial tissue-skeletal muscles-bones-internal organs and cardiovascular system. This has far reaching effects in setting the foundation for understanding how the adjustment works in systemic and autonomic changes by being able to measure and reproduce functional changes within the brain as direct sequellae.


The evidence also reveals that only chiropractic adjustments (high velocity-low amplitude) render these findings and mobilization of joints conclusively do not. In addition, muscle impairment does not automatically improve with symptoms abating creating the necessity for both short and long-term care. This indicates that the deficits in proprioception and motor control, rather than the pain itself, may be the main factors defining the clinical picture and chronicity of various chronic pain conditions.



1. Lantz, C. A. (1995). A review of the evolution of chiropractic concepts of subluxation. Topics in Clinical Chiropractic, 2(2). Retrieved from

2. Coronado, R. A., Gay, C. W., Bialosky, J. E., Carnaby, G. D., Bishop, M. D., & George, S. Z. (2012). Changes in pain sensitivity following spinal manipulation: A systematic review and meta-analysis. Journal of Electromyography Kinesiology, 22(5), 752-767.

3. Reed, W. R., Pickar, J. G., Sozio, R. S., & Long, C. R. (2014). Effect of spinal manipulation thrust magnitude on trunk mechanical activation thresholds of lateral thalamic neurons. Journal of Manipulative and Physiological Therapeutics, 37(5), 277-286.

4. Thalamus. (2015). Wikipedia. Retrieved from

5. Mohammadian, P., Gonsalves, A., Tsai, C., Hummel, T., & Carpenter, T. (2004). Areas of capsaicin-induced secondary hyperalgesia and allodynia are reduced by a single chiropractic adjustment: A preliminary study. Journal of Manipulative and Physiological Therapeutic, 27(6), 381-387.

6. Gay, C. W., Robinson, M. E., George, S. Z., Perlstein, W. M., & Bishop, M. D. (2014). Immediate changes after manual therapy in resting-state functional connectivity as measured by functional magnetic resonance imaging in participants with induced low back pain. Journal of Manipulative and Physiological Therapeutics, 37(9), 614-627.

7. Daligadu, J., Haavik, H., Yielder, P. C., Baarbe, J., & Murphy, B. (2013). Alterations in coritcal and cerebellar motor processing in subclinical neck pain patients following spinal manipulation. Journal of Manipulative and Physiological Therapeutics, 36(8), 527-537.



Dr. Mark Studin is an Adjunct Associate Professor of Chiropractic at the University Of Bridgeport College Of Chiropractic, an Adjunct Assistant Professor of Clinical Sceinces at Texas Chiropractic College and a clinical presenter for the State of New York at Buffalo, School of Medicine and Biomedical Sciences for post-doctoral education, teaching MRI spine interpretation and triaging trauma cases. He is also the president of the Academy of Chiropractic teaching doctors of chiropractic how to interface with the legal community (, teaches MRI interpretation and triaging trauma cases to doctors of all disciplines nationally and studies trends in healthcare on a national scale ( He can be reached at 631-786-4253.


Dr. Bill Owens is presently in private practice in Buffalo and Rochester NY and has created chiropractic as the primary spine care referral for the primary care medical community and emergency rooms in both regions.  He is an Associate Adjunct Professor at the State University of New York at Buffalo School of Medicine and Biomedical Sciences and is an Adjunt Assistant Professor of Clinical Sceinces at the University of Bridgeport, College of Chiropractic and Texas Chiropractic College.  He also works directly with doctors of chiropractic to help them build relationships with medical providers in their community. He can be reached at or 716-228-3847  

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Published in Brain Function

Harvard Report Points to Chiropractic Care for Pain Relief

& The Safety of the Chiropractic Adjustment


Noah Herbert, D.C., CCSP®

William J. Owens DC, DAAMLP


A recent article released by Harvard Health Publications at Harvard Medical School points to chiropractic care as a form of pain relief. There are currently many Americans that seek out chiropractors, but many people don’t realize the wide variety of treatments that a chiropractor can provide for pain relief. The article states “while the mainstay of chiropractic is spinal manipulation, chiropractic care now includes a wide variety of other treatments, including manual or manipulative therapies, postural and exercise education, ergonomic training (how to walk, sit, and stand to limit back strain), nutritional consultation, and even ultrasound and laser therapies. In addition, chiropractors today often work in conjunction with primary care doctors, pain experts, and surgeons to treat patients with pain.”

While this is nothing new for the chiropractic community, it may serve to further educate the public as to the many tools a chiropractor possesses to help patients. While the majority of research on chiropractic has focused on spinal manipulation, or adjustment of the spine, for pain relief, there have been studies done on the effectiveness of chiropractic for treating musculoskeletal pain, headaches, asthma, carpal tunnel syndrome and fibromyalgia (Harvard Health Publications). The author goes on to state “a recent review concluded that chiropractic spinal manipulation may be helpful for back pain, migraine, neck pain and whiplash.” It should be pointed out there have been reports of serious complications, including stroke, but this has been shown to be extremely rare and some studies suggest this may not be directly caused by the treatment provided by the chiropractor (Harvard Health Publications).

Spinal manipulation, or adjustment of the spine, is a term used to describe providing a high velocity, low amplitude thrust to the vertebra. Chiropractors use this technique to correct the body’s spinal alignment to relieve pain and improve function and to allow the body to heal itself. Treatment usually takes between 10 to 20 minutes and most patients are scheduled 2-3 times per week initially. Patients generally see improvement of their symptoms in the first two to three weeks (Harvard Health Publications).

Harvard Medical School is now saying what chiropractors have been saying for over 100 years and although their article was based on pain, it does add more evidence to the false rhetoric of chiropractic patients having a greater risk of stroke. In the future, reports from Harvard and other medical academic institutions will embrace the growing body of scientific evidence of the varied maladies that respond to chiropractic care.



  1. Harvard Health Publications. (2015). Chiropractic Care for Pain Relief. Retrieved from

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Published in Low Back Problems

The Effects of Chiropractic Spinal Adjustments on Heart Rates

A report on the scientific literature 


William Owens DC, DAAMLP

"Heart rate is the number of heartbeats per unit of time - typically expressed as beats per minute (bpm) - which can vary as the body's need for oxygen changes, such as during exercise or sleep. The measurement of heart rate is used by medical professionals to assist in the diagnosis and tracking of medical conditions. It is also used by individuals, such as athletes, who are interested in monitoring their heart rate to gain maximum efficiency from their training...Heart rate is measured by finding the pulse of the body. This pulse rate can be measured at any point on the body where an artery's pulsation is transmitted to the surface - often as it is compressed against an underlying structure like bone - by pressuring it with the index and middle finger. The thumb should not be used for measuring another person's heart rate, as its strong pulse may interfere with discriminating the site of pulsation" (Wikipedia, 2010, "Heart rate").
"The autonomic nervous system (ANS or visceral nervous system) is the part of the peripheral nervous system that acts as a control system functioning largely below the level of consciousness, and controls organ functions. The ANS affects heart rate, digestion, respiration rate, salivation, perspiration, diameter of the pupils, micturition (urination), and sexual arousal. Whereas most of its actions are involuntary, some, such as breathing, work in tandem with the conscious mind" (Wikipedia, 2010, "Autonomic nervous system").
For our conversation, it is this autonomic nervous system that largely controls the heart rate. Dr. I Kestin, Consultant Anesthesiologist, Derriford Hospital, UK, stated in 1993, “The heart will beat independently of any nervous or hormonal influences. This spontaneous rhythm of the heart (called intrinsic automaticity) can be altered by nervous impulses or by circulatory substances, like adrenaline. The muscle fibers of the heart are excitable cells like other muscle or nerve cells...This automatic rhythm of the heart can be altered by the autonomic nervous system. The sympathetic nervous system supply to the heart leaves the spinal cord at the first four thoracic vertebra, and supplies most of the muscle of the heart...There are nervous reflexes that effect heart rate. The afferents are nerves in the wall of the atria or aorta that respond to stretch. The aorta contains high pressure receptors. When the blood pressure is high these cause reflex slowing of the heart to reduce the cardiac output and the blood pressure. Similarly, when the blood pressure is low, the heart rate increases, as in shock. Similar pressure receptors are found in the atria. When the atria distend, as in heart failure...there is a reflex increase in the heart rate to pump the extra blood returning to the heart. When there is a sudden reduction in the pressure in the atria the heart slows" (
Increased heart rate can lead to cardiomyopathy, damage of the heart muscle and according to Cook, Togni, Schaub, Wenaweser, and  Hess in 2006, “Since 1980, it is known that resting heart rate (RHR) is a prognostic factor in coronary diseased patients. Data from the Coronary Artery Surgery Study (CASS) published last year underline the prognostic importance of RHR for morbidity (time to rehospitalization), as well as total and cardiovascular mortality. Heart rate proves to be the best predictor after myocardial infarction, in patients with congestive heart failure, as well as in patients with diabetes mellitus or hypertension. In addition, it was found that elevated RHR is also strongly associated with mortality in the general population” (
p. 2387).
It has been the independent clinical observation and conclusion over the course of 30 years by Dr. Mark Studin, one of the author's of this article, that post chiropractic adjustment patients have experienced lowering heart rates and subsequent high blood pressures. Dr. Studin states, “Many patients have reported that their increased heart rates have abated for long periods of time.”
Budgell and Polus reported in The Journal of Manipulative and Physiological Therapeutics (2006) that chiropractic adjustments of the thoracic spine were associated with significant heart rate values and influenced the autonomic output of the heart, meaning that heart rates generally lower with the chiropractic adjustments because of the shift in the neurological communication of the autonomic nervous system (to the parasympathetic nerves) causing the heart to slow or normalize.

This study by Budgell and Polus offers potential answers to many as to why patients' heart rates spontaneously spike for no apparent reason. The spine, although a great influence the nervous system, has often been overlooked in the clinical arena as the prime cause for cardiac issues. The authors of this article want to emphasize that chiropractic care has a positive effect for many conditions, including cardiac, and should be considered in conjunction with all other health care specialists, as clinically indicated, as a conclusive diagnosis to rule out life-threatening illnesses must be rendered.


1.  Wikipedia, The Free Encyclopedia. (2010, July). Heart rate. Retrieved from

2.  Wikipedia, The Free Encyclopedia. (2010, July). Autonomic nervous system. Retrieved from
3.  Kestin, I. (1993). Control of heart rate, Physiology, 3(3), 1. Retrieved from
4.  Cook, S., Togni, M., Schaub, M. C., Wenaweser, P., & Hess, O. M. (2006). High heart rate: A cardiovascular risk factor?, European Heart Journal, 27(20), 2387-2393.
5.  Budgell, B., & Polus, B. (2006, October). The effects of thoracic manipulation on heart rate variability: A controlled crossover trial. Journal of Manipulative and Physiological Therapeutics, 29(8), 603-610.

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