In the eyes of the public, the chiropractic vertebral subluxation theory has confused the definition of the word subluxation, a common medical term. Unlike the mysterious, undetectable and asymptomatic chiropractic vertebral subluxation complex alleged to be a cause of disease, a real vertebral subluxation, that is, an orthopedic subluxation, can be a cause of mechanical and neuromusculoskeletal symptoms but has never been associated with organic disease.
Subluxations: Real and Imaginary
An orthopedic subluxation, recognized and named as such since the days of Hippocrates, is a painful partial dislocation. Simple misalignment of a vertebra, also referred to as a subluxation, is commonly caused by disc degeneration, curvatures, spondylolysis, and structural abnormalities. Such a subluxation may or may not be mechanically symptomatic and can be seen on a plain x-ray image. In the absence of pathology such as disc herniation or osteophyte formation, these common vertebral subluxations or misalignments rarely affect spinal nerves and have never been associated with organic disease. Spinal nerves supply musculoskeletal structures. The bodys organs are supplied primarily by autonomic nerve ganglia and plexuses located outside the spinal column and by cranial and sacral nerves that pass through solid bony openings, providing overlapping nerve supply independent of any one spinal nerve that passes between two vertebrae.
An orthopedic subluxation, a true vertebral misalignment, or a mechanical joint dysfunction that affects mobility in the spine is not the same as a chiropractic subluxation that is alleged to cause disease by interfering with nerve supply to organs. Such a subluxation has never been proven to exist. There is no plausible theory and no credible evidence to support the contention that nerve interference originating in a single spinal segment can cause an organic disease.
Unable to provide evidence that commonly occurring vertebral misalignment can cause organic disease, advocates of the subluxation theory have reasoned that there must be some other type of joint dysfunction that can affect general health. They have chosen, by consensus, to call this undetectable lesion a vertebral subluxation complex, which embraces the holistic nature of the human body, including health, well-being, and the doctor/patient relationship as well as the changes in nerve, muscle, connective, and vascular tissues which are understood to accompany the kinesiologic aberrations of spinal articulations.1
Some chiropractors claim to be able to locate these elusive subluxations by using surface electromyography, thermography, vibratory instruments, leg length checks, or by palpating the spine.
A largely ignored landmark review of the literature by a Ph.D. and a chiropractor (Nansel and Szlazak), published in 1995, concluded that there is not a single appropriately controlled study to indicate that any dysfunction in structures of the spinal column is a cause of organic disease.2 The review noted that pain and other symptoms referred from a spinal segment can create overt signs and symptoms that can mimic, or simulate (rather than cause), internal organ disease, lending no support to the vertebral subluxation theory. Spinal nerves are commonly irritated or compressed, causing pain and other symptoms in the musculoskeletal structures supplied by the affected nerve. But even the most severe compression of a spinal nerve does not cause organic disease.
A review of the current evidence on the epidemiology of the subluxation construct (Mirtz, et al, 2009) also failed to find any credible evidence supporting the chiropractic vertebral subluxation theory. This paper, authored by three chiropractors and a Ph.D., concluded that No supportive evidence is found for the chiropractic subluxation being associated with any disease process or of creating suboptimal health conditions requiring intervention. Regardless of popular appeal this leaves the subluxation construct in the realm of unsupported speculation. This lack of supportive evidence suggests the subluxation construct has no valid clinical applicability.3
While there is justification for use of the word subluxation when referring to a mechanical-type spinal problem, there appears to be no justification whatsoever for suggesting that a chiropractic subluxation can affect general health.