The Purpose of Myofascia in the Distribution of Circulation and Innervation
By Thomas Griner (published article Dynamic Chiropractic)
Once you understand the role of myofascia, you can see that an adhesion of these fascia would be as horrendous as an adhesion of the pleural fascia (pleurisy). You will also see two other important roles which skeletal muscles serve in addition to moving bones and maintaining alignment.
Before discussing the consensus of information on myofascia, I would like to insert some more chiropractic history relevant to giving muscles consideration.
In July 1979, "A Hypothesis" by William Nelson,DC, appeared in Family Physician (volume 1, number 6). In the article, Dr. Nelson stated: "Since 1895, we have been using the vertebra adjustment as the sine qua non of chiropractic. This is analogous to medicine still using bloodletting as a basic from which to grow. It is alleged that chiropractic started out with the premise that a subluxation impinged a nerve and the patient's trouble started. We recognize that the subluxation has something to do with the disease process. While we speak knowingly of correcting the subluxation, we also recognize that it is not as simple as that.
"After the adjustment, the vertebra is often in the same place, even though the symptoms have been ameliorated. The truth is that the newer techniques using the muscular system as effectors do in fact correct subluxations better, faster, and with more lasting effects."
Unfortunately, Dr. Nelson did not say whether his statement that symptoms disappear even though the subluxation was unchanged was from personal trial or awareness of the trials that were done at the Los Angeles College of Chiropractic. Since these trials did not produce the desired results, they were not widely publicized. I became aware of them from Henry Higley,DC,MS, who was the head of research at LACC while I was enrolled there. He tried to recruit me for the research program, as we both had worked for NASA.
In those trials, researchers took and measured immediate pre- and post-manipulation x-rays to try to prove that symptomatic change was due to improved vertebral alignment. The failure of the trials led to a change from referring to subluxation instead to the subluxation complex.
This was what Dr. Homewood suggested in his book The Neurodynamics of the Vertebral Subluxation, which was mentioned in an earlier article. (Editor's note: see "Which Comes First: The Malstructural Misalignment or the Malfunctional Muscle Imbalance?" in the January 1 issue.) In a section titled "Antiquated Theories," Dr. Homewood cites physiological experiments showing that "pressure upon nerves does not materially alter their ability to conduct." He called for revising the explanation of the mechanism by which disease is related to structural distortion.
Now back to the role of myofascia. Each muscle is encased in an epimysial fascia. This fascia will abut periosteal fascia, telesubcutania, or other epimysial fascia. The space between adjacent epimysial fascia provides a protective corridor for arteries, veins, nerve trunks and lymph ducts. Here we see muscles act as cushions, as long as they do not have elevated levels of hypertonicity that can turn the cushion hard.
Other examples include the femoral portion of the gluteus maximus, which acts as a cushion for the ischial bone when sitting, and the abductor hallicus and abductor digiti minimi, which form cushions for the heel bone, etc. In addition, rhythmic muscle activity acts upon the veins and lymph ducts to propel their fluids back to the heart with the help of the valves in these vessels.
Again, impaired muscle tone will undermine this pumping activity. Nerve branches, arterioles, venules and lymph ductules penetrate the epimysial sheath to run in corridors formed by adjacent perimysial fascia which divide the muscle fibers into fascicular bundles. The soleus muscles are the only ones in which the veins proper send collaterals through the epimysium into the interfascicular corridors. This is because the muscle-pumping action of these veins must produce a higher pressure in order to propel the venous blood upward against the weight of the column of blood above it.
The interfascicular spaces contain two other structures that are critical in understanding how muscles malfunction. You will find the muscle spindles here attached to two different points along the perimysial sheath. The spindle is subjected to an average of the activity of all the muscles fibers operating within the enclosed fascicle. A single lymph ductule attaches to the spindle sac.
Scattered throughout the interfascicular corridors are hundreds of shunts (arteriovenous anastomoses). These bypass ducts have thicker muscle walls at the arteriolar end than the arterioles they branch off of, and serve two purposes.
When you are asleep and at your basal metabolic level, so few capillaries are open that they would not pass enough blood to maintain the minimum venous return volume needed to keep the heart from losing its prime as a pump. More blood passes through the bypass shunts to maintain that critical volume. How much more? The blood flow through muscles at maximum exertion (all capillaries open) is 20 times the flow at basal level, yet the oxygen utilization is 60 times greater, indicating that at basal level, twice as much blood goes through the bypass shunts as through the capillaries.
This action is partly due to the muscle venous pumping system being inactive at basal level. The shunts also allow blood to remain in motion so that as the capillaries open and close, the blood needs only be diverted and not accelerated or braked to a stop. The only structures that penetrate the perimysial fascia to run through the corridors provided by adjacent endomysial fascia are motor nerve fibers and capillary beds. The motor nerves then penetrate the endomysial fascia to form an end plate on the enclosed muscle fiber. Remember that the alpha motor nerve is called the final common pathway indicating that there are numerous synapses on the dendrites of the cell body in the spinal cord.
The pyramidal nerve coming down from the motor cortex is only one very important member of a committee that determines if and how much the motor nerve will fire. In computer terminology, the synapse is a combination of and, or and nor gates. The next article will present the consensus of information regarding the metabolism of the muscle fibers.