Proverbs are informal, common-sense truths about often-repeated errors. They act as a preliminary yardstick when evaluating whether or not a statement fits the fabric of experience. For example, we are cautioned against putting the cart before the horse. Therefore, when it is stated that “structure is primary to function”, common sense says that is like putting the passive, structural cart ahead of the active, functioning horse.
Formal conclusions fall into the realm of logical truths, and can provide a higher level of verification. Charles Darwin established a relevant truth when he said, "Function alters structure." This statement would force the conclusion that mal-structures, unless from injury or abnormality, would not be etiologies, but rather signs of an underlying malfunction (even abnormalities are the sign of underlying DNA malfunctions).
In his chiropractic textbook The Neurodynamics of the Vertebral Subluxation, A.E. Homewood writes: "Tone is that degree of contraction shown by normal resting muscle, and which maintains the attachments in proper anatomical relationship". This statement, which fits well with both the proverb and the logical truth, is corroborated in numerous physiology texts, and indicates that functional ‘muscle tone’ is responsible for structural alignment. In the same text, Homewood quotes D.D. Palmer saying, "Life is the expression of tone", which sentence was the basic principle of the original Palmer chiropractic. Normal muscle tone indicates good health, while disturbed muscle tone indicates disturbed health, and disturbed tone in turn disturbs structure.
Is palpation – where one encounters muscles before bones – detecting subluxations or disturbed muscle tone? D.D. Palmer wrote, "Those situations which modify centripetal flow of neural impulses disturb the centrifugal flow, and thereby modify the tone”. D.D. Palmer may not have been aware of the terms efferent and afferent, but he was insightful enough to realize that disturbed neural feedback would create disturbed muscle tone (which controls structural alignment). And skeletal muscle would appear to be the logical place to look for a primary disturbance, since the efferent nerve signal generators are all protected inside the central nervous system, while the afferent nerve signal generators are out in the "jungle."
The quest then is to determine what factors other than injury, toxins, or tumors could disturb muscle feedback. Emotions would operate efferently (generally), not afferently (specifically). When turning to textbooks for clues, one faces the fact that physiology and anatomy texts contain material tailored for use in the practice of medicine. Medicine's divide-and-conquer approach to health care utilizes neurologists, angiologists, gastroenterologists, ophthalmologists, urologists, and even proctologists, but no muologists (or myologists). The muscles, which constitute more than half the mass of the body, are orphans.
The result is disconnected and sometimes contradictory information on muscle function. Even the biochemistry books use the word "probably" when discussing muscle metabolism.
This author's original quest for accurate information on the skeletal muscle system therefore required searching for trends of information and pooling information from different sources, including two different editions of Guyton's Physiology. As it happened, the older edition had some relevant information that had been removed in the newer edition; not because the information was obsolete, but to make room for material better tailored to medical practice.
More pertinent information on physiology was gleaned from the detailed two-volume set Mountcastle's Physiology. This was rounded out with the physiology text by Betne and Levy. For anatomy, there was Grant's Anatomy; Lockhart/Hamilton/Fyfe; the more informative cross-section anatomy text by Eycleshmyer and Schoemaker; the texts by Han/Kim and Cahill/Orland; and Gray's Anatomy (the unabridged British edition, not the U.S. version).
It was disconcerting to discover that Gray's Anatomy, which is considered the premier anatomy text in the world, was a font of misinformation regarding muscles. The text is identified as Gray's Anatomy, not Gray's Anatomy and Physiology, yet they could not resist encroaching into the field of physiology with resulting error. Muscle tone is a physiological response, not an anatomical structure. Gray's insists that all the physiology texts are wrong when they say muscle tone is residual contraction in a normally resting muscle (a point on which physiology texts unanimously agree).
Through lack of understanding of how electromyography operates, they claim there is no residual contraction in a relaxed muscle and created the misconception of ligamentous support well inside the range of motion. Physiologists agree that ligaments only operate at the limits of the range of motion.
Gray's also meddles in discussing the different functional types of muscle. Again, function is physiology, not anatomy. Gray's claims there are three types of muscle fibers in human skeletal muscle tissue: slow-twitch aerobic muscle, fast-twitch anaerobic, and fast-twitch aerobic. As a result, many sports medicine articles extolling the existence of the fast-twitch aerobic fiber have been written and published.
The physiology books agree, however, that fast-twitch aerobic fibers do not exist in primates. Humans are the top primate. Why this fiber is not needed in primates will be discussed in a future writing on the consensus on muscle metabolism.
