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Chiropractic Biophysics (CBP) Technique

Spine modelChiropractic Biophysics (CBP) is a system of chiropractic spinal analysis and care developed by Donald D. Harrison, M.S., DC, M.S.E., Ph.D., and Glenn Harrison, B.S., DC

The approach to improved patient well-being, as designed by these doctors, is a mechanistic one. To some extent, these mechanistic concepts are justified in that the spine and nervous system have many machine-like qualities. The spine is composed of bones, muscles, blood vessels and neural networks which resemble beams, motors, hydraulics and computers, respectively. Ball and Carlson1 have stated, “The use of engineering modeling in biological systems is now commonly accepted as a logical means of approaching highly complex mechanisms.”

Chiropractic Biophysics Technique

CBP applies the sciences of mathematics, physics and biophysics to the practice and theory of chiropractic. While the simple analogies of a bone “stuck” or “out of place” may serve doctors well when communicating with patients regarding spinal adjustments or some form of therapy, they hardly reflect the degree of sophistication which is necessary in communicating with the rest of the scientific community.

The plight of our profession can be simply summed up in the following statement from the report of the New Zealand Commission of Inquiry Into Chiropractic: “The exact nature of such defects (subluxations) has not yet been demonstrated; nor has the mechanism by which its apparent effects are produced.” The 1975 NINDS workshop on the status of spinal manipulative therapy made the observation that “there was no quantitative or qualitative reproducible description of subluxation.”

Chiropractic biophysics is addressing these shortcomings by combining the discipline of science, the foundational principles of chiropractic and the application of technical skills to attempt to elucidate the truth about what we do, how we do it and how we can do it better. CBP attempts to understand and apply the universal laws which govern the behavior of matter and energy and their interactions in biological systems. The result of over 12 years of development is an ever-expanding and evolving base of work and literature relating to the science of what chiropractic is and does. Currently, the CBP technique represents a full spine and pelvis corrective/rehabilitative procedure having a firm foundation in the sciences of mechanics and physics and providing both a qualitative and quantitative model of chiropractic practice.

The overall goal of the CBP technique is to restore normal three-dimensional human posture. Methods include “mirror image” posture adjustments, rehabilitative exercises, cervical extension traction and manual procedures. In CBP, the overall posture or global positioning of the spinal column is targeted for correction, as opposed to individual spinal segments.

In CBP, the optimum static position of the upright human spine is established with the Harrison spinal model. A subluxation is considered to be any postural deviation from this mathematical norm. The model represents the most complete chiropractic effort to date to establish what constitutes “normal.”

Although not perfect, the Harrison model is a starting point and a reasonable clinical objective for corrective care. It is expected that as our knowledge expands, so too will the model expand and evolve.

The CBP protocol of care begins with the initial patient encounter and a case history, followed by a traditional orthopedic and neurological examination. The patient is then analyzed for abnormal posture in every possible degree of freedom of the skull, thoracic cage and pelvis.

Next, an exacting series of radiographs is performed which are then analyzed using geometry to obtain information for formulating care plans and later to serve as an objective standard against which to evaluate the efficacy of care. Following careful consideration of pertinent clinical findings, especially the correlation of the patient’s three-dimensional posture with its two-dimensional X-ray image, a patient’s case is either accepted or referred to an appropriate specialist.

Patients who are accepted for care are generally assigned to one of two regimens (i.e., acute or corrective care). Factors, which might influence the appropriate type of care, could be numerous, such as the nature of their specific complaint, the magnitude of their postural distortions and the degree of pathophysiology associated with subluxation degeneration. Patients who are selected for acute care would receive a program of care perhaps not unlike that of many non-CBP offices. They would undergo “diversified”-type adjustments (both long- and short-lever) to restore segmental mobility, cryotherapy to reduce localized inflammation, passive and active stretching and massage as indicated to reduce spasm and myofascial involvement. Acute care programs may also apply to corrective care patients who enter the office symptomatic.

The CBP corrective care regimen includes the use of drop table and upper cervical instrument-assisted adjustive procedures, as well as a variety of corrective extension traction procedures and corrective postural exercises. It is not the methods themselves, which are unique to CBP, but rather the rationale behind their use and the way in which these tools are employed to accomplish stated clinical objectives.

The following is a summary of basic methods currently in use.

In chiropractic biophysics, abnormal human posture is analyzed and corrected be means of what is termed “mirror-image” adjustments. Basically this is done by first analyzing the standing posture in three dimensions and then stressing the patient’s abnormal posture into its exact opposite, or “mirror,” image. Once the patient has been pre-stressed into the mirror image, a light adjustive force is applied. Adjustive forces are generally applied to the atlas transverse process with either a toggle-type adjustment or by means of a cervical adjusting instrument. Adjustive forces may also be introduced to the lower back area by the use of a drop table adjustment with force applied to the sacroiliac or femur head areas.

The purpose of mirror image adjustment is to introduce mechanical stimulation to proprioceptors and encourage the brain to reconsider the faulty postural patterns which have become habituated overtime. It is precisely these habituated postural patterns which are a major source of chronic spinal dysfunction and which result in spinal resistance to correction which all practitioners have experienced.

Mirror image adjustments may be performed with the patient in either the prone, supine, side posture or standing positions. Correction to normal posture is then verified by pre- and post-adjustment postural examinations.

Since adaptation of muscular structures is a process that takes place over an extended period of time, repetition of positive forces into the affected tissues is necessary to effectively achieve and maintain postural correction. These simple techniques alone can often be quite effective, as demonstrated in a 1986 study by Klein and Sobel of neck pain patients, in which 59 percent received significant long-term relief from performing postural exercises for their conditions. Harrison’s mirror image exercises are set up individually, based on the patient’s particular abnormal posture configuration, unlike many generic, “one-size-fits-all” exercise programs.

Mirror image exercise procedures effectively reeducate the body by targeting those muscle groups and their associated global movements, which effect a more permanent correction of the patient’s subluxated posture.

One of the most common postures, which presents in the chiropractic office is that of cervical hypolordosis/kyphosis with the patient’s head in an anterior weight-bearing position. In chronic cases, ligaments will have creeped shorter and adapted to the abnormal postures. Due to their specific mechanical properties, ligamentous tissues do not often respond well to the rapid loading forces which constitute the chiropractic adjustment. Anyone familiar with the sigmoid-shaped load-deformation curves obtained from testing spinal ligaments realizes that rapid loading forces affect only the elastic range of the ligaments. Loads must be applied over 20 to 30 minutes to affect the viscous and plastic regions of the load-deformation curves.

Consequently, the primary purpose of cervical extension traction is to provide a long duration or slow adjusting force to those soft tissues that have contracted over time and therefore tend to perpetuate the patient’s subluxated state.

A variety of traction methods are currently being employed by CBP practitioners. Performed in the office, these methods may require times that range from 10 to 20 minutes, according to the doctor’s discretion and patient tolerance. Many patients also receive a home traction device so that they may actively participate in their recovery program.

By use of these methods, CBP field practitioners are experiencing great success in restoring cervical curves. As evidence of the success of this approach, a recent controlled clinical trial demonstrated an average increase of the cervical lordosis of 13.5 degrees versus no statistically significant change in the control group.


The chiropractic biophysics technique is unique for several reasons. It provides a specific therapeutic goal (the Harrison model of ideal upright posture). It correlates the patient’s three-dimensional posture with precise radiographic analysis to help eliminate much of the false data, which are inherent in analysis based on X-rays alone. It effectively addresses the overall posture of the patient by means of mirror image adjustive procedures, and it seeks to rectify long-term soft tissue changes by means of extension tractioning and rehabilitative exercise programs which are tailored individually for each patient. Through the application of knowledge borrowed from the fields of physics and mathematics and university biophysics, we are bringing clinical results into line with our philosophical tenets.

Learn more. Contact Ballantyne Advanced Chiropractic and schedule an appointment.


About the author:

Donald D. Harrison, DC, is the developer of the CBP technique. He holds BS and MS degrees in mathematics, masters in mechanical engineering, and also holds a PhD in math in addition to his Doctor of Chiropractic degree. He is the publisher of the American Journal of Clinical Chiropractic, which is published quarterly.


1.Ball, L.D., and Carlson, L.E., Experimental Mechanics of the Spine, 6th Annual Biomechanics Conference on the Spine, Boulder, Cob.t Univ. of Colorado, 1975.

2.Harrison, D.D., “Abnormal Postural Permutations Calculated as Rotations and Translations From an Ideal Normal Upright Static Spine,” chapter 6, In:Chiropractic Family Practice,J. Sweere, Ed., Gaitherburg, Md.: Aspen Publishers, 1992.

3. Cochran, C., A Primer of Orthopedics Biomechanics, Churchill Livingstone, 1982.

4. White, A.A., and Panjabi, M.M., Clinical Biomechanics of the Spine, Philadelphia: 1.8.Lippincott Co., 1978.

5. Chasal, J., Tanguy, A., Bourges, M., Caurel, C., Escande, G., Cuilbot, M., and Vameuville, C., “Biomechanical Properties of Spinal Ligaments and a Histological Study of the Supraspinal Ligament in Traction,” I. Biomechanics 3:167-176,1985.

6. Chow, D.H.K., Luk, K.D.K., Leong, J.C.Y., and Woo, C.W., “Torsional Stability of the Lumbosacral Junction: Significance of the Iliol Ligament,” Spine 14:611 -615, 1989.


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