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Neurophysiology

Spinal adjustments alter afferent input and influence the central integrative state of the brainstem and cortex. Chiropractic stimulates the proprioceptive system, regulates tone, and shifts autonomic balance. This reorganization of neurological input may explain many of the observed systemic benefits of chiropractic care.

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Neurophysiology of Chiropractic: How Subluxation Affects the Body

Introduction: Chiropractic care is grounded in the premise that correcting vertebral subluxations – often defined as misalignments or dysfunctional segments of the spine – can restore optimal nervous system function and health mdpi.com. The World Health Organization even classifies the vertebral subluxation as a biomechanical spinal lesion (ICD-10 code M99.1) mdpi.com. Classic chiropractic theory describes a Vertebral Subluxation Complex with five key components: Neuropathophysiology, Kinesiopathology, Myopathology, Histopathology, and Pathophysiology. In simple terms, a subluxation can irritate nerve tissue, alter joint motion, imbalance muscles, inflame local tissues, and lead to long-term degenerative or systemic changes. Modern research is beginning to illuminate the neurophysiological mechanisms behind these effects. Below, we discuss each component – and the related “loops” between the spine, spinal cord, and brain – along with current evidence. Chiropractic adjustments appear to induce real, measurable changes in the nervous system that correlate with improvements in mobility, pain, inflammation, and overall health.

Neuropathophysiology: Nerves and Spinal Cord Function

Neuropathophysiology refers to how subluxation affects nerve tissue. A misaligned vertebra may compress or stretch nearby nerves (e.g. spinal nerve roots) or even exert tension on the spinal cord itself, disrupting communication between the brain and body. Pioneering work by neurosurgeon Alf Breig demonstrated how loss of the normal cervical curve can “tether” the spinal cord, leading to cord deformation and even microscopic damage (myelomalacia) over time chiro-trust.org. Breig observed that long-standing posture deformities (such as cervical kyphosis) put adverse mechanical tension on the cord and risk permanent neurological injury chiro-trust.org. This illustrates the importance of neuropathophysiology: a subluxation or poor alignment physically stressing the nervous system.

Even mild or moderate nerve impingement can have consequences. Compressed or irritated spinal nerve roots may lead to pain, numbness, or tingling along the nerve’s distribution (classic “pinched nerve” symptoms), but importantly, even sub-clinical irritation may alter nerve signaling. For example, sensory nerves from spinal joints fire abnormally when a joint is fixated or inflamed, leading to distorted feedback to the spinal cord and brain. This phenomenon, sometimes called dysafferentation, means the brain is receiving an altered stream of information from the body.

Over time, dysafferentation can contribute to maladaptive neural plasticity – essentially “wiring” the central nervous system in a way that perpetuates pain or dysfunction mdpi.com. In fact, subluxations are described as “central segmental motor control problems” resulting in maladaptive neural changes that interfere with the CNS’s self-regulation nature.com. Chiropractic adjustments aim to reduce nerve impingement and normalize nerve signaling, and research shows they indeed influence the nervous system. Spinal adjustments alter the afferent input (sensory signals) from the spine to the brain, which in turn produces changes in central nervous system function nature.com. For instance, one EEG study found that adjusting spinal segments led to changes in brain activity in regions involved in sensory processing and pain modulation nature.com. These neurophysiological changes suggest that correcting a subluxation can optimize the brain-body communication loop. By removing pressure or irritation from nerves, chiropractic adjustments may restore proper signaling along spinal cord tracts and between the body’s receptors and the brain. This is consistent with patient reports of improved nerve function – e.g. better sensation or strength – after an adjustment. In summary, the neuropathophysiological aspect of subluxation highlights that nerve interference is real and can be mitigated: relieving that interference through chiropractic care can normalize reflexes and improve the flow of information through the spinal cord and nerves nature.com.

Kinesiopathology: Restoring Alignment and Movement

Kinesiopathology is the biomechanical component of the subluxation complex. It refers to abnormal motion or alignment of spinal joints. When a vertebra is even slightly misaligned or fixated (locked in place), it disrupts the spine’s normal kinematics, leading to altered movement patterns and strain on the musculoskeletal system. Joints that don’t move properly also fail to stimulate their mechanoreceptors (the stretch and position sensors in joint capsules and muscles), depriving the central nervous system of accurate proprioceptive input mdpi.com. This is critical, because our brain relies on a continuous stream of sensory feedback from the spine to coordinate posture and movement. An improperly moving spinal segment essentially sends the wrong signals up the chain (via dorsal column and spinocerebellar tracts), and the brain may respond by controlling muscles and posture less optimally down the chain (via corticospinal and vestibulospinal tracts). In other words, a stiff or misaligned segment can throw off the whole “sensorimotor loop” between the body and brain.

Chiropractic adjustments directly address kinesiopathology by realigning the joints and restoring proper motion. A spinal manipulation (high-velocity, low-amplitude thrust) can unlock a fixated joint or nudge a misaligned vertebra toward its correct position. This not only improves the mechanical alignment but also reactivates normal proprioceptive signaling. Research in chiropractic neurology has shown that adjustments improve proprioceptive processing from the spine nature.com. For example, studies using somatosensory evoked potentials and joint position sense testing have found that after cervical spine adjustments, patients have better joint position accuracy and improved sensorimotor integration mdpi.com. Essentially, the brain gets a clearer picture of what the body is doing once the spinal joints are moving freely. Chiropractic care has been shown to influence cerebellar and cortical processing of information from the spine, likely due to this restoration of healthy afferent input mdpi.com nature.com.

It’s also important to view kinesiopathology in the context of whole-body mechanics. The body functions as a biotensegrity structure – a continuous network of muscles, fascia, and bones distributing mechanical forces theamericanchiropractor.com. A disturbance in one part (like a subluxated vertebra) can transmit abnormal tension throughout the system. As Dr. Stephen Levin (originator of the biotensegrity concept) describes, our bones “float” in a tension network, and any load on one area is shared by the whole structure lazarspinalcare.com. Thus, a spinal misalignment can cause compensatory strain in distant areas (for example, a stuck pelvic joint might lead to a twist in the spine and tilted shoulders). This interconnectedness explains why chiropractors often examine the entire posture. Forward head posture or a loss of the normal spinal curves, for instance, dramatically increases stress on spinal joints and supporting muscles chiro-trust.org.

Over time, such kinesiopathological changes contribute to degenerative disc disease and osteoarthritic changes (the body lays down extra bone or fibrous tissue in response to chronic abnormal forces). Indeed, it’s well documented that most people show some degenerative changes in the spine with age – a reflection that long-standing joint dysfunction (subluxations) have cumulative effects musculoskeletalkey.com. Chiropractic adjustments help enforce proper biomechanics, which not only improves immediate range of motion but also may slow or prevent these degenerative processes by correcting the underlying imbalances.

In summary, kinesiopathology is about the loop between alignment and movement: a subluxation distorts that loop, while an adjustment restores it. By normalizing joint motion, chiropractic care improves mechanoreceptor feedback to the spinal cord and brain, leading to better coordination and balance. Patients often report feeling lighter or more flexible after an adjustment – a subjective sign that their biomechanics have improved. Objective measures support this, as regular chiropractic care has been associated with improved posture and gait. Maintaining proper spinal movement through chiropractic may therefore be considered a preventative strategy against the cascade of dysfunction and degeneration that follows poor biomechanics musculoskeletalkey.com.

Myopathology: Muscle Imbalances and Reflexes

Myopathology in the subluxation complex refers to the changes in muscle function that accompany spinal misalignments. Around a subluxated vertebra, some muscles become tight, tense, or go into spasm, while others may weaken or atrophy. These changes are often mediated by altered nerve supply or protective reflexes. For example, if a spinal segment is painful or inflamed, the body may reflexively contract the small stabilizer muscles around it (like the multifidi or rotatores) in an attempt to guard the area – a phenomenon known as muscle spasm. Over time, that chronic spasm reduces blood flow and causes fatigue in the muscles, and can even lead to fibrous adhesions. Conversely, if a nerve root is chronically compressed by a subluxation or disc issue, the muscles it innervates might receive reduced neural drive, resulting in weakness or delayed activation. In either case, the normal symmetrical coordination of muscles is disturbed.

These muscle changes also feed back into the nervous system. Consider the stretch reflex loop: muscle spindles detect stretch and send signals to the spinal cord, which then reflexively contracts the muscle. If a joint is not moving correctly, the muscle spindles in that area may become overactive (causing excessive tone) or under-stimulated (leading to poor tone and coordination). A common example is the upper cervical subluxation: it can cause certain neck muscles to become hypertonic (tight) and others hypotonic, contributing to imbalance and even symptoms like tension headaches. There is also a pain-muscle-pain cycle: pain from a subluxation causes muscle guarding; tight muscles then produce more pain and inflammation, which in turn perpetuates the cycle. This illustrates a vicious loop between the nervous system and muscles.

Chiropractic adjustments help re-establish normal muscle function by breaking this cycle. Adjusting a subluxated segment often results in immediate relaxation of hypertonic muscles – many patients feel an instant release of tension or “knots” in the area that was adjusted. At the same time, muscles that were weak or inhibited may regain strength as normal nerve communication is restored. High-quality studies have demonstrated objective changes in muscle function following adjustments. One notable experiment measured leg muscle strength and reflexes before and after a single chiropractic adjustment: after the spinal manipulation, subjects showed a significant increase in maximum voluntary contraction force (over 16% increase in leg muscle strength), accompanied by a drop in the H-reflex threshold (indicating a normalization of spinal cord reflex excitability) pubmed.ncbi.nlm.nih.gov. This suggests that the adjustment enhanced the descending drive from the brain to the muscle and/or modulated the spinal reflex circuits pubmed.ncbi.nlm.nih.gov. In other words, the brain was able to activate the muscle more effectively after the subluxation was corrected. Similarly, a series of studies by Haavik and colleagues have found improved muscle control and higher muscle electrical activity (EMG power) in athletes and even stroke patients after chiropractic adjustments mdpi.com. These changes are evidence of neural plasticity – the nervous system’s ability to adapt – in action. By removing interference (the subluxation), the nervous system recalibrates how it recruits and balances muscles.

Over longer term care, chiropractic adjustments may also influence muscle health structurally. Chronic low back pain patients often show fatty infiltration and atrophy in their deep spinal muscles, a myopathology that correlates with instability. Corrective exercises and regular adjustments can promote better activation of these muscles, helping to restore endurance and support to the spine. One MRI study even found that many “healthy” individuals have some degree of lumbar paraspinal muscle degeneration by middle age musculoskeletalkey.com – implying that subtle dysfunction builds up over time undetected. Regular chiropractic care, by keeping those segments moving and nerves firing, could help keep spinal muscles healthier and more symmetric. In summary, the myopathology component underscores that subluxations are not just about bones – they profoundly affect muscles too. Through the intimate loops of reflexes and motor control, a spinal adjustment can relax spasmed muscles, energize weak ones, and restore a balanced muscular support for the spine pubmed.ncbi.nlm.nih.gov. Patients often notice better range of motion and strength after an adjustment, which is the myopathology aspect being resolved.

Histopathology: Inflammation and Tissue Healing

Histopathology refers to the cellular and tissue changes that occur around a subluxation. When a joint is misaligned or not moving properly, it can cause micro-injury or irritation to the surrounding soft tissues – including ligaments, joint capsules, discs, and adjacent nerves/blood vessels. The body responds to such stress with an inflammatory reaction. You can imagine a stuck facet joint in the spine as a kind of mild sprain: the tissues may swell and inflammatory chemicals (cytokines) accumulate locally. This inflammation further sensitizes nerve endings in the area (producing pain) and can cause that familiar stiff, swollen feeling around the affected joint. If the subluxation persists, the ongoing inflammation can lead to fibrosis (scar tissue formation) and other tissue changes – much like an untreated sprained ankle can develop chronic swelling and scar tissue.

The histopathological component is essentially the link between mechanical dysfunction and the biochemical immune response. It also has a two-way relationship with the other components: inflammation can irritate nerves (worsening neuropathophysiology), trigger pain reflexes and muscle spasm (myopathology), and even reduce motion (because swollen tissues restrict mobility – kinesiopathology). This local inflammation can sometimes spill into systemic circulation as well, contributing to elevated inflammatory markers in the blood.

Exciting research in recent years suggests that chiropractic adjustments have measurable anti-inflammatory effects. A 2010 clinical study examined patients with chronic low back pain, measuring their blood levels of inflammatory cytokines before and after a course of chiropractic care. After just 9 adjustments (over roughly 2 weeks), the patients showed a significant reduction in pro-inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP) – trending back toward the levels seen in healthy individuals pmc.ncbi.nlm.nih.gov. In other words, the chiropractic treatment produced a normalization response in these inflammation markers pmc.ncbi.nlm.nih.gov. This is a remarkable finding, as IL-6 and CRP are major indicators of systemic inflammation and are often elevated in chronic pain conditions. The same study noted that prior research had observed immediate cytokine changes after a single adjustment, including reductions in tumor necrosis factor-alpha (TNF-α) and interleukin-1 (IL-1) pmc.ncbi.nlm.nih.gov. These are key inflammatory mediators associated with tissue injury and pain sensitization. Notably, the adjustments did not raise levels of substance P (a pain neurotransmitter), indicating the effect was specifically on inflammatory pathways pmc.ncbi.nlm.nih.gov.

What could explain these anti-inflammatory effects? One theory is that by restoring motion and reducing nerve irritation, adjustments diminish the source of provocation that was triggering inflammation. Joint mobilization likely improves circulation of fluids (blood and lymphatic flow), helping to drain inflammatory exudates from the area. There is also the concept of the “gate control” and higher-order pain modulation: adjustments may prompt the spinal cord and brain to release anti-inflammatory neurotransmitters or activate the vagus nerve’s calming, anti-inflammatory pathway. Indeed, the nervous and immune systems are tightly interconnected – the neuroimmune loop means that reducing nociceptive (pain) input from a subluxation can lead the brain to down-regulate the inflammatory response. Some authors have likened an adjustment to “hitting reset” on an irritated segment, allowing the tissue to move from a chronic inflammatory state toward normal healing.

Clinically, the reduction of inflammation and swelling is observed as decreased pain, less stiffness, and faster recovery from injuries. Patients often report that after an adjustment they feel less localized tenderness and notice that any soft tissue swellings (like a taut muscle knot or spasm) go down. By addressing the histopathology component, chiropractic care not only relieves discomfort but also promotes tissue repair. This can prevent the long-term consequences of unchecked inflammation, such as excessive scar tissue or degenerative changes in joints. In short, the histopathological aspect highlights chiropractic’s role in helping the body resolve inflammation naturally. As inflammation subsides, nerve pressure eases and mobility improves – showing how this ties back into the other components in a positive feedback loop. Emerging scientific evidence of cytokine modulation gives credence to the long-held observation that patients under regular chiropractic care often report getting sick less frequently or recovering faster from injuries – potentially due to lower overall stress and inflammation in their systems pmc.ncbi.nlm.nih.gov.

Pathophysiology: Systemic and Long-Term Effects

The final component, Pathophysiology, encompasses the chronic, long-term, and systemic consequences that can arise from uncorrected subluxations. In many ways it is the culmination of the other four components over time. A persistently misaligned spinal segment will undergo pathophysiological changes such as degenerative joint disease (e.g. osteoarthritis of the facet joints, thinning of intervertebral discs) and sclerotomal changes (like bone spur formation). These changes can be seen on X-rays or MRI as the “wear and tear” of the spine, but they are not simply due to aging – they often reflect imbalances in load and motion that have gone uncorrected. Indeed, as one chiropractic text noted, most people eventually show signs of disc and connective tissue degeneration (histopathology) and chronic inflammation/biochemical changes by middle age, and in turn develop reduced mobility (kinesiopathology) and local nerve disturbances (neuropathophysiology) musculoskeletalkey.com. In other words, subluxation complex lesions may be far more common in the population than acute back pain is, operating silently until enough damage accumulates to cause symptoms musculoskeletalkey.com. Chiropractic’s focus on prevention addresses this by correcting imbalances before they manifest as overt disease.

Beyond the spine itself, chronic subluxations can have widespread health effects through the nervous system. The spinal cord is like a “switchboard” connecting the brain to all organs via the autonomic nerves. A dysfunction in the spine can perturb the autonomic nervous system output – for example, a thoracic subluxation might irritate sympathetic nerve fibers that travel to the heart or lungs, potentially contributing to visceral dysfunction (somato-visceral reflex). Prolonged sympathetic overactivity (the “fight or flight” stress response) is associated with higher blood pressure, poorer immune function, and hormonal imbalances. Conversely, improving spinal function may help rebalance autonomic tone. Case studies and clinical observations over decades have reported improvements in patients’ digestion, respiration, cardiovascular function, and other systemic issues after chiropractic adjustments, which are thought to be mediated by normalized autonomic nerve supply to organs. A famous placebo-controlled study in 2007 provided dramatic evidence: patients with high blood pressure and misaligned C1 vertebrae (atlas) received a specialized atlas adjustment. Their blood pressure dropped significantly – equivalent to the effect of two blood-pressure medications – and the improvement persisted for weeks sciencedaily.com. In the control group that received a sham adjustment, no change was noted. The mechanism is not fully understood, but it’s suspected that correcting upper cervical misalignment reduces stress on the brainstem and vagus nerve, thereby lowering systemic blood pressure through autonomic regulation sciencedaily.com. This example illustrates how a single subluxation in the neck had a whole-body effect on a vital health parameter.

Another long-term effect of subluxation is the impact on the central nervous system’s plasticity and stress response. Chronic pain signals from spinal dysfunction can lead to central sensitization – the spinal cord and brain become hyper-responsive, causing even mild stimuli to be perceived as pain. This is seen in conditions like chronic low back pain and fibromyalgia. By alleviating the source of those signals, chiropractic adjustments may help reverse central sensitization. In fact, a 2024 neuroimaging study found that chiropractic care led to changes in brain networks involved in pain processing and even altered the default mode network (a brain network tied to stress and mood) mdpi.commdpi.com. Over a 4-week period, patients receiving adjustments had improvements not only in pain, but also in mood, anxiety, and fatigue levels, alongside measurable EEG changes mdpi.commdpi.com. The authors concluded that many of the health benefits of chiropractic care are due to altered brain activity (neuroplastic changes) resulting from improved spinal function mdpi.commdpi.com. Such findings reinforce the idea that chronic musculoskeletal stress can impair overall well-being, and relieving that stress allows the nervous system to restore harmony in various bodily systems (including mental health, sleep regulation, and immune function).

Speaking of the immune system: chronic stress and pain from subluxations can contribute to immunosuppression (via cortisol and sympathetic neurotransmitters). Correcting subluxations may therefore boost immune resilience indirectly. There is some evidence of increased immune biomarkers (like IgA) in patients after adjustments, and reduced pro-inflammatory cytokines as discussed earlier. Moreover, improved nervous system balance (especially enhancing parasympathetic activity) can promote better organ function – sometimes called the Chiropractic Wellness Effect by practitioners. While more research is needed in this realm, it aligns with the holistic chiropractic observation that patients under regular care often report fewer illnesses and a general sense of wellness.

Finally, pathophysiology includes postural and structural health, which has been linked to longevity and disease risk. A landmark study in a geriatric population found that individuals with hyperkyphotic posture (“dowager’s hump” or an excessively flexed thoracic spine) had a 44% higher rate of mortality than those without, primarily due to increased atherosclerotic heart disease deaths chiro-trust.org. Poor spinal alignment in the sagittal plane can impair breathing mechanics, strain the heart, and elevate sympathetic tone – all systemic effects. Chiropractic interventions that improve posture (restoring curves, reducing forward head carriage) could thus have profound long-term health benefits, potentially reducing these risk factors. Even simple quality-of-life measures – the ability to remain active, mobile, and pain-free in older age – are better in those who maintain their spinal function. Pathophysiology reminds us that a small imbalance today can become a big problem tomorrow if not addressed. Chiropractic’s preventive approach, by correcting those imbalances, aims for better long-term health span.

Conclusion: The 5 Keys – and the Loops that Connect Them

In summary, the neurophysiology of chiropractic reveals that a vertebral subluxation is not an isolated bone out of place, but a complex lesion affecting multiple systems. The five components – neuropathophysiology (nerve function), kinesiopathology (joint motion), myopathology (muscle activity), histopathology (tissue state), and pathophysiology (global health) – are interrelated through feedback loops in the nervous system. A subluxation can set off a chain reaction: misalignment causes inflammation, which irritates nerves, which alters muscle tone, which further distorts biomechanics, and over time can lead to chronic degeneration and systemic stress. Conversely, a chiropractic adjustment can cascade positive effects through those same loops: restoring proper motion eases inflammation, which calms the nerves, which allows muscles to relax and strengthen, which supports better alignment – all of which helps the body function as it should. Modern scientific studies, from cellular inflammation assays to fMRI brain scans, are validating these effects. Adjustments have been shown to reduce inflammatory

cytokines pmc.ncbi.nlm.nih.gov, improve muscle strength and reflexes pubmed.ncbi.nlm.nih.gov, normalize autonomic function (as seen in blood pressure changes) sciencedaily.com, and induce beneficial neuroplastic changes in the brain mdpi.commdpi.com.

Chiropractic is inherently neurological care: by caring for the spine, we influence the central nervous system. This is done in a non-invasive, preventive manner, aiming to harness the body’s innate recuperative powers (a concept Dr. D.D. Palmer described as maintaining the body’s “tone”). The loops between the spinal cord and brain – whether it’s the pain modulation loop, the proprioceptive loop for balance, or autonomic loops regulating organs – all depend on clear, uninterrupted signaling. Chiropractic adjustments help “tune” those loops to an optimal state. As an authoritative review succinctly stated, many health benefits of chiropractic care are likely due to improved central neural function mdpi.com. By addressing all five components of the subluxation complex, chiropractic doesn’t just crack joints – it fine-tunes the entire neuromusculoskeletal system, which can have far-reaching benefits for a patient’s vitality and well-being.

References:
 

  1. Breig A. Adverse Mechanical Tension in the Central Nervous System. Almqvist & Wiksell, 1978. (As referenced in Chiropractic and Sagittal Posture – ChiroTrust)chiro-trust.org

  2. Holt K. et al. (2019). The effects of chiropractic spinal manipulation on central processing of tonic pain: a pilot study using EEG.nature.comnature.com Scientific Reports 9, 6925.

  3. Haavik H. et al. (2024). Neuroplastic Responses to Chiropractic Care: Broad Impacts on Pain, Mood, Sleep, and Quality of Life. Brain Sci. 14(11):1124mdpi.commdpi.com.

  4. Niazi IK et al. (2015). Changes in H-reflex and V-waves following spinal manipulation. Exp Brain Res. 233(4):1165-1173pubmed.ncbi.nlm.nih.govpubmed.ncbi.nlm.nih.gov.

  5. Boucher JP et al. (2010). Inflammatory response following a short-term course of chiropractic treatment in subjects with and without chronic low back pain. J. Manipulative Physiol. Ther. 33(3): 168-177pmc.ncbi.nlm.nih.govpmc.ncbi.nlm.nih.gov.

  6. Kado DM et al. (2005). Hyperkyphotic posture predicts mortality in older community-dwelling men and women: a prospective study. J Am Geriatr Soc. 53(10):1667-1673chiro-trust.org.

  7. Bakris GL et al. (2007). Atlas vertebra realignment and achievement of arterial pressure goal in hypertensive patients: a pilot study. J. Human Hypertension 21(5):347-352sciencedaily.comsciencedaily.com.

  8. Roth GB. (2022). The Biotensegrity Matrix – the Fabric of Life: A New Paradigm in Health Care. The American Chiropractor, Feb 2022 [Article]theamericanchiropractor.comtheamericanchiropractor.com.

  9. Alanazi MS et al. (2025). Neuromuscular Response to High-Velocity, Low-Amplitude Spinal Manipulation – An Overview. Medicina (Kaunas) 61(2):187mdpi.commdpi.com.

  10. Welch A, Boone WR. (2019). Sympathetic and parasympathetic responses to specific chiropractic adjustments of the cervical spine. Int J Neurosci. 129(3):283–296. (Demonstrated direct ANS changes post-adjustment)pmc.ncbi.nlm.nih.gov

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