Do you know that studies show that the fascia is more painful than the skin or the muscles?
(Schidler et al, Pain 2014, Pain Rep 2018)
The fascial network is one of our richest sensory organs. Because fascia is innervated, it can also be an important pain generator. That being said, the contribution of fascia to painful syndromes cannot be underestimated. Fascia contains both mechanoreceptors and nociceptors and also has a proprioceptive function.
Let’s take a closer look at exactly how fascia is innervated:
Fascia is densely innervated by mechanoreceptors (Golgi end organs, Pacini corpuscles, Ruffini endings, free nerve endings), which are responsive to manual pressure (Table 1.1).
The original thought was that Rolfing-type techniques used by Structural Integrators were effective because they helped to elongate the collagen in the tight fascial tissue. However, it is now understood that the nervous system plays a far larger role and most probably brings about the changes seen clinically when using fascial techniques (be it Structural Integration, Stecco Fascial Manipulation, MSM or Myofascial Induction)
Robert Schleip, renowned leader of the Fascia Research Group at the University of Ulm in Germany, states:
“In myofascial manipulation an immediate tissue release is often felt under the working hand. This amazing feature has traditionally been attributed to mechanical properties of the connective tissue. Yet studies have shown that either much stronger forces or longer durations would be required for a permanent viscoelastic deformation of fascia. A change in attitude in myofascial practitioners from a mechanical perspective toward an inclusion of the self-regulatory dynamics of the nervous system is suggested.”(Schleip 2003)
Fascia contains many nociceptors, mostly A and C fiber nociceptors, which may explain descriptions of fascia pain as “throbbing, stinging and hot.” This may lead the therapist into thinking that the pain perceived by the patient is due to neuropathic pain when, in reality, the pain is coming from fascia. A myriad of tiny unmyelinated free nerve endings are found almost everywhere in fascial tissues, but particularly in periosteum, in endomysial and perimysial layers, and in visceral connective tissues (Mense 2007; Tesarz et al. 2011). Human data indicate that the fascia is more sensitive to pain than either the skin or the muscles (Gibson 2009; Deising et al. 2012).
Deep fascia also seems to have a proprioceptive function and so may affect motor control. It is hypothesized that myofascial expansions could guarantee motor coordination among different segments of the body, giving anatomical support to myokinetic chains (Stecco C. 2015a).
Fascia and the autonomic nervous system appear to be intimately connected. Stimulation of mechanoreceptors leads to a lowering of sympathetic tonus as well as a change in local tissue viscosity. Studies of the anatomy of the thora- columbar fascia reveal a close relationship between the sympathetic nervous system and the pathophysiology of fascial disorders. Forty percent of thoracolumbar fascia innervation consists of sympathetic fibers, known to have vasoconstrictor effect on blood vessels, which may then lead to ischemia in fascia. This may help explain the phenomenon of increased intensity of pain with psychological stress, which increases activation of the sympathetic nervous system (Willard et al, 2012).