What Is A Chiropractic Adjustment?
Chiropractic adjustment or manipulation is a manual therapy technique where the doctor applies a controlled, high-velocity low-amplitude (HVLA) thrust in a specific vector of a given dysfunctional joint, that is determined through the palpation process, to restore the joint’s proper function and related neuromusculoskeletal tissues.
*HVLA thrust — a thrust that is applied very quickly over a short distance.
Joint manipulation takes the joint into what’s called the paraphysiological space. It is within the paraphysiological space that joint cavitation — the “popping” sound — occurs.
With more and more emerging scientific studies, we now know more about the neurophysiological effects of a joint manipulation than we ever have before. Turns out manipulation not only changes biomechanics of the joint but also has various neuromusculoskeletal effects.
Neurophysiological Effects of Manipulation
- Sensory inflow. Biomechanical changes caused by spinal manipulation are thought to have physiological consequences via their effect on the inflow of sensory information to the central nervous system. Muscle spindle and Golgi tendon organ afferents are up-regulated by spinal manipulation. These receptors play a crucial role in proprioception and in decreasing the risk of injury.
- Central facilitation.Many chronic pain patients have a “hypervigilant” nervous system that allows subthreshold or innocuous stimuli to access central pain pathways. Numerous studies show that spinal manipulation increases pain tolerance.
- Reflex motor output. Spinal manipulation evokes paraspinal muscle reflexes and alters motor neuron excitability — increasing power output of muscles innervated by the affected nerve roots or located near the joint being manipulated.
- Excitatory and inhibitory effects.If a muscle is hyperactive, manipulation will bring it back toward optimal; if it is underactive, manipulation will likewise bring it back toward optimal. Joint manipulation acts as a kind of “reset button.”
- Biomechanical theories. Four main mechanisms include release of entrapped synovial folds or meniscoids, restoration of buckled motion segments, reduction in articular or periarticular adhesions, and normalization of hypertonic muscle by reflexogenic effect.
- Pain–spasm–pain cycle. Pain causes muscular hyperactivity (spasm), and spasm reflexively produces pain. Manipulation is proven to break this self-perpetuating cycle.
- Neural plasticity. Manipulation alters the excitability of low-threshold motor units, changes synaptic efficacy of the Ia synapse, and increases corticospinal excitability — producing increases in muscle strength and cortical drive in the cerebellum, basal ganglia, prefrontal cortex, and primary sensory and motor cortex.
- Natural pain killer. Via its effect on the autonomic nervous system, joint manipulation leads to opioid-independent analgesia.
A Brief History of Chiropractic Adjustment
The earliest historical reference to manipulative therapy in Europe dates back to 400 BCE. Initially, spinal manipulation was thought to correct a structural deficit of a given joint — whether scoliosis, subluxation, or even dislocation. Later it was discovered that the nerve roots exit the spinal column through small spaces called neural foramen and that joint dysfunctions could disrupt the function of the innervated tissues.
Today we know joint manipulation has far more benefits than once thought, including central neuroplastic changes, alterations in motor neuron excitability, improved muscle strength, increased cortical drive, activation of the descending pain modulation system, and optimization of central sensitization.
How We Use Adjustments at FRI
At Functional Restoration Institute, we utilize evidence-based motion palpation protocols specific to each joint of the human body. The doctor determines the dysfunctional joints through these protocols, which require the patient to dynamically move through different motion planes specific to the joint in question. Based on the motion palpation results, the doctor performs a joint manipulation on the dysfunctional segments and then re-assesses to confirm the manipulation was successful.