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Posture, etiology of a syndrome

Paolo Platania
Posturology guidelines and
interdisciplinary case study

  
  
Posture
  
Posturology
  
  
The backstage
  
 
Definition | Features | Physiology | Pathology | Etiology

Posture

Posture has been defined in a thousand ways, none of which compliant to the intended meaning of the author; the absence of agreed conventions leaves the boundaries of the subject still ambiguous and undefined, as such, explanation of the concept by each author, prior to expose it, is a prerequisite.

In order to provide general meaning to the word posture, including all the variables that it implicitly involves, it is mandatory to remark that posture may NOT be confined to human beings, NOR to upright position and NOT EVEN to awake state or to other contextual restrictions.

Posture is the shape, position and motion of live beings equipped with motor system, it's goal is to describe the way motor system implements all hierarchical layers of motion:

  1. reflexive motor vital functions (eg. respiration, heartbeat, swallowing..)
  2. reflexive motor vital defence (eg. cough reflex, gag reflex, vasoconstriction..)
  3. reflexive motor environmental tasks (eg. stretch reflex, crossed-extension reflex..)
  4. spontaneous motor environmental tasks (eg. congenit motor abilities like walking..)
  5. voluntary motor environmental tasks (eg. acquired motor abilities like skiing, striking poses..)

Posture precise description is achieved by a bidimensional matrix resulting by the cross-correlation of being classification and motor model.

To achieve a being classification, the sample has to be catalogued according to individual features within it's breed:

To achieve a relyable motor model the avaulation has to be performed under as many perspectives as possible in order to have all the variables included, measurable and reproducible:

Putting being classification and motor model together we get the postural model of the evaluated individual.

Implementing classes of postural models allows to contrast an individual postural model with a mean postural model within it's species or species parameters (eg. same age, same gender, same anatomical features...) and to understand variations amongst individuals/race/gender/age/pathology or whatever other perspective.

Within this broad definition, the material hereafter exposed covers human posture and the symptoms, mechanics, pathomechanics and etiopathogenesys of the postural disorder.

Features

Posture internally acts on each part of human anatomy in different ways: provides life, defence, motion and degeneration; every motor system action generates both immediate (motion) and delayed (degeneration) responses. Basic requisite to approach the hypothesis and observations hereafter exposed is the agreement and understanding of author's perspective.

Postulates of posture:

  1. Functional hierarchy: with life preservation as the priority, meaning that postural strategy never conflicts with higher priority functions. Understanding this is mandatory to interpret each pathological behaviour;
  2. Crafted by natural selection: meaning that every postural strategy comes out from million years of human anatomical/environmental relationship evolution, thus, neither meant to manage each anatomical/environmental combination (eg. white bear in the saharan desert) nor to adapt to new environments (sitting at a desk) nor to diffused aberrations (high heels, wrong medical therapies) never experienced during human race evolution (all of which situations most of civilized human beings indeed experiment). Understanding this, helps explaining such a high incidence of postural strategy failures causing pathologies so uncommon in the less civilized human and animal beings.
  3. Dismantled by loss of natural selection: meaning that pathologies are growing as natural selection has been interrupted thousands years ago, at least in civilized world, given to the loss of selecting conditions, as such, unsuited and pathologic characters are transmitted to the progeny contributing to weaken global mankind strenght and health.

Variables of posture:

Priority dependence: Anatomy dependence: Internal stimuli dependence: Environmental stimuli dependence:

Task dependence: static, motor, difficulty;

History dependence: learning ability;

Awareness dependence: awake, asleep, REM sleep.

Physiology

Physiologic posture is the way human evolution has developed postural strategies to accomplish all the tasks human body is requested to, thus, it merges common functional (objective) and individual (subjective) criteria together with environmental characteristics (variable), making challenging drawing rules for prototyping it. Plenty of parameters, along posturology short life, have been theorized to describe physiologic upright position and/or other common postural position in order to identify every possible deviation from what is considered normal, this catalogue of observations is the first logical stage to get a physiologic posture model but is considered way far from being completed.

The most intuitive way to draw a physiological motor model is entrusting the sampling criteria to natural selection itself (or what's left of it). The measure unit of motor functionality is the motor outcome, in other words, the motor performance level, which can be described as:

Suitable criterias for identifying segments of population meeting requisites of motor physiology are: occupational and etnic.

Occupational segments of population are, in order of relyability:

  1. Classic ballet etoile: the incredible technical difficulties requires the highest functional level, the further restrictive aesthetic requisite makes a high level ballet artist the most relyable specimen for physiologic motor model, meeting either quantitative and qualitative motor performance levels.
  2. Top level (absolute level) athletes in every specialty: the level of measurable performance reached makes these athletes quantitatively superior, whereas, their repeatable and undiscussed superiority allows to consider them either quantitatively and qualitatively superior,
  3. High level athletes and classic ballet artists: they offer a good likelyhood of posture physiology but not as high as the above, the relative level reached doesn't allow to exclude the presence of some extent of postural disorder.

Etnic segments of population are considered a higly relyable way to draw a physiologic motor model, segments identification is challenging and require a wide statistical base, according to observation the author proposes:

  1. Black etnies from poorly civilized africa: the presence of environmental selecting condition, the lack of economic resources and the low likelyhood of ratial contamination, contribute to enforce this population by means of natural selection,
  2. Other etnies from less civilized worlds: same as the above but extended to other etnies.

Despite the apparently reductive criterias for targeting the population, it is opinion of the author that sampling controls according to relyable predetermined categories reasonably yields a set of physiologic motor models, as such, collecting each sampleís anthropometric motor and static features would provide a relyable being classification and related physiologic motor model.

In the absence of relyable parameters to which entrust the definition of physiologic posture, not only simplifying is restrictive but it may reveal dangerous referring to clinically accepted (but not physiology dictated) habits to identify deviations from normal posture.

Several findings are recurrent in healthy posture, what follows is a general (but not comprehensive) guideline based on the authorís self evaluation, population observation and literature review. The guideline lists some conditions observed in physiologic motor performance.

General:

Head:

Thorax: wide frontal chest expansion and poor dorsal kyphosis;

Shoulder girdle: shoulder and arms freedom and symmetry of swing during walking and running;

Pelvic girdle:

Pathology

Postural disorder is a sub class of posture, it is exactly defined by the differences between the postural model of an individual with an ongoing pathology and the postural model of the same individual in healthy condition or, with more approximation, by the differences between the postural model of an individual with an ongoing pathology and the average postural model of healty individuals of the same class. Although posture includes reflexive (involuntary) as well as voluntary motor tasks, postural disorder is commonly referred as the disorder of the involuntary motor component only, as disorders of the voluntary motor component are more related to behavioural disorders and are approached differently.

Only after posture physiology definition is agreed it is possible to talk about posture pathology. A diffuse way of thinking is to consider a pathology only a painful symptomatic manifestation, comparing asymptomatic degenerations and asymmetric/disharmonious motion to health, and using overworked slogans like "we all are asymmetric" or "95% of the population has asymptomatic spine degenerations" to motivate the unexplainable. The way physiology "thinks" is different, it considers pathological every motor strategy that provides function in an different way (compensated) from what was originally meant.

Postural distortions always produce a damage, itís severity and symptoms arising depend on postural impairment harmfulness and individual tolerability threshold. All of this allows to say that these damages are directly related to the initial postural impairment and that their symptomatic manifestation is unpredictable. This "time bomb" feature of postural disorders is itís worst enemy misleading diagnosis of the initial noxious stimulus, moreover, postural distortions are never perceived by the majority of the population due to slowness in symptoms progression and poor self awareness, making it challenging motivating them a postural diagnosis.

Damages severity and symptoms onset depend on tolerability threshold: and on postural disorder harmfulness:

The stages of the postural diagnostic process are:

Pathological process:

The practical example of this multi stage diagnostic approach will appear clearer in the The case study section.

Etiology

The meaning of the word is well known but has to be further tailored to fit the postural requirements, the steps of the ordinary etiological diagnostic process are:

Whereas the stages of the postural etiology diagnostic process are:

First primaries process:

Second primaries process:

The practical example of this multi stage diagnostic approach will appear clearer in the The case study section.

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Posture, etiology of a syndrome - ©2008 Paolo Platania