Sunday, April 27, 2008
How important is functional leg length compared to the mechanics of breathing? How important is the coupling of L4-L5 motion in right lateral flexion compared to the mechanics of breathing?
Structure vs. Function
Does structure determine function or does function determine structure, or does each determine the other, and if the latter, how can it be? The answers to these questions seem to be matters of definition, personal paradigm and recognition of the driving purpose of the natural order.
In the inorganic world structure may be regarded merely as a mechanical collocation of parts in a whole. But in the biological world, structure is a mechanical collocation of parts adapted to an end.
One cannot argue that “structure leads to function” is a popular belief yet when evolutionary forces are considered one is drawn to concepts such as Wolff’s Law: Function precedes structure. A look at biology gives clinician a unique understanding. That understanding is that efficient function and behavior in the external environment leads to adaptable structure. Saving and economic use of resources drives the individual and the species. Efficient function with available finite resources determines the survival of an individual. With enough time and offspring, structure adapts to save resources and energy. What can be said definitively is that structure and function are interdependent with the biologic drive of survival being efficient utilization of available resources.
In fact ineffective processing can not only be learned (efficiency driven) depressed functions but other physiological states labeled asthma, atopic diseases, mental health conditions. Evidence at the molecular, cellular, systems, behavioral, and the analytical computational levels is converging to suggest a view that addiction represents a pathological usurpation of the neural mechanisms of learning and memory that under normal circumstances serve to shape survival behaviors related to the pursuit of rewards and the cues that predict them.
These addictive behavior patterns and pre-frontal executive functions become efficient at the level of the CNS. Chiropractic has long discussed the role of the vertebral subluxation in mental health. Because of flawed afferent input, an aberrant output begins.
This model of the VSC, with the subluxation altering afferent input that leads to inefficiency of processing and thus physiopathology, has larger ramifications. The chiropractor should consider that humans have the ability to alter development, physiology, growth, and behavior in response to different internal or external environmental conditions. These responses represent critical assessments of both external and internal environment.
A tonal chiropractic technique approach looks at the controlling systems of the body. Even traditional segmental and postural concerns like subluxation degeneration (also called osteoarthritis) are now being targeted as a functional (tonal) issue.
Although there are many risk factors (such as age, family history, and obesity) associated with the development of osteoarthritis (OA), only trauma is known to cause OA. The neuromuscular system, through CNS-controlled afferent-efferent programs, controls the amount and kind of movement occurring at a joint, so it is this system that is ultimately responsible for ensuring that joint tissues are not damaged to the point of developing OA during normal day-to-day activities. Tonal chiropractic techniques concern themselves with influencing the controlling systems of the body.
Most of the current research shows that a neuromuscular protective model based on central pattern generators (CPGs) can explain this clinical reality. CPGs are subconscious motor programs that run during dynamic equilibrium and movements. They control balance, static posture, and background tone in all joints and movements. These programs are developed, then remembered (recalled) as needed. These afferent/efferent programs are driven by instantaneous energy efficiency. Understanding the role of CPGs can best reconcile much heretofore ambiguous information pertaining to the development and progression of OA (subluxation degeneration) in stable and unstable joints. These CPGs (programs) can explain the continuance and maintenance of the pain in patients. Tonal chiropractic techniques concern themselves with influencing the controlling systems of the body.
The vertebral motion unit is rich in proprioceptors and nociceptors. Biomechanical alterations, from trauma or from inefficient movement patterns (chronic), may result in an alteration of normal nociception and mechanoreception. Thus, aberrant afferent input into the CNS leads to dysponesis.
Dysponesis is defined by Dorland's Medical Dictionary as follows:
A reversible physiopathologic state consisting of unnoticed, misdirected neurophysiologic reactions to various agents (environmental events, bodily sensations, emotions, and thoughts) and the repercussions of these reactions throughout the organism. These errors in energy expenditure, which are capable of producing functional disorders, consist mainly of covert errors in action-potential output from the motor and pre-motor areas of the cortex and the consequences of that output.
Dysponesis does not mechanistically describe a specific allopathic (ICD-9 labeled) condition but rather relates to human homeostasis and dis-ease. It relates to human health as a function of the whole. It is philosophically and scientifically suitable for a tonal technique chiropractor to detect a patient with dysponesis (errors in energy expenditure) secondary to vertebral subluxation complex or causing a ‘perceived misalignment’. All that is necessary are the tools for the chiropractic assessment / analysis that evaluates CNS processing and efficiency at all levels (local, regional, global) of physiology and the understanding of that processing.
D.D. Palmer emphasized the importance of “tone” in the dynamics of health and disease. Dr. Palmer in his text, The Chiropractic Adjuster, stated in 1910, “ Life is an expression of tone. Tone is the normal degree of nerve tension. Tone is expressed in function by normal elasticity, strength, and excitability...the cause of disease is any variation in tone.”
DCs must find a strategy, which is effective in disclosing these covert errors in energy expenditure caused by inefficient input and correcting them. Tonal chiropractic techniques concern themselves with influencing the controlling systems of the body that manage energy expenditure are one answer to the search for assisting the CNS in handling afferentation.
Inappropriate afferent input can lead to aberrant efferent output leading, and in the long term, to a state of dis-ease or abnormal energy expenditure. This inefficient energy expenditure leads to depressed function of other body systems as the finite energy is partitioned or mobilized to other parts of the CNS. The appropriate chiropractic adjustment adds positive physiological input into the CNS that allows resources to be saved and thus the surplus resources are able to utilized.
If this depressed functioning remains for any length of time, neuroplasticity takes over and the brain will “prune” connections to allow for a more efficient firing and ATP utilization of this depressed functional state. This pruning and efficiency is based on ATP and neurological resource utilization not on the long term effects it will have on the organism. The CNS and natural selection do not make ‘moral or rational ‘decisions on the long term consequences of increasing efficiency of deleterious programs. The drive is to save resources in the immediate short term. One ‘learns” to be sick efficiently.
These disadvantaged functional states could be a simple decreased filtering of nociception as it travels through the thalamus for filtering, integration and modification. Resources (ATP, neurotransmitters, etc are being utilized for other greater prioritized programs) rather than filtering an achy knee. Or they could be inefficient biomechanics of the sacrum and pelvis. They could indicate inefficient filtering of extraneous sensory information (auditory, kinetic, visual) and abnormal descending pre-frontal inhibition into the thalamus (or other areas) and thus lead to ADD-like symptoms.
These depressive functional states could lead to neurophysiological partitioning and mobilization of energy resources and lead to an efferent program called dysautonomia. All these outputs can be termed dis-ease or will eventually develop into an ICD-9 AMA-labeled diagnosis.