Evidence of a new hidden neural network into deep fasciae

Abstract

It is recognized that different fasciae have different type of innervation, but actually nothing is known about the specific innervation of the two types of deep fascia, aponeurotic and epymisial fascia. In this work the aponeurotic thoracolumbar fascia and the epymisial gluteal fascia of seven adult C57-BL mice were analysed by Transmission Electron Microscopy and floating immunohistochemistry with the aim to study the organization of nerve fibers, the presence of nerve corpuscles and the amount of autonomic innervation. The antibodies used were Anti-S100, Anti-Tyrosine Hydroxylase and Anti-PGP, specific for the Schwann cells forming myelin, the sympathetic nerve fibers, and the peripheral nerve fibers, respectively. The results showed that the fascial tissue is pervaded by a rhomboid and dense network of nerves. The innervation was statistically significantly lower in the gluteal fascia (2.78 ± 0.6% of positive area, 140.3 ± 31.6/mm2 branching points, nerves with 3.2 ± 0.6 mm length and 4.9 ± 0.2 µm thickness) with respect to the thoracolumbar fascia (9.01 ± 0.98% of innervated area, 500.9 ± 43.1 branching points/mm2, length of 87.1 ± 1.0 mm, thickness of 5.8 ± 0.2 µm). Both fasciae revealed the same density of autonomic nerve fibers (0.08%). Lastly, corpuscles were not found in thoracolumbar fascia. Based on these results, it is suggested that the two fasciae have different roles in proprioception and pain perception: the free nerve endings inside thoracolumbar fascia may function as proprioceptors, regulating the tensions coming from associated muscles and having a role in nonspecific low back pain, whereas the epymisial fasciae works to coordinate the actions of the various motor units of the underlying muscle.

Dose-Dependent Pain and Pain Radiation after Chemical Stimulation of the Thoracolumbar Fascia and Multifidus Muscle: A Single-Blinded, Cross-Over Study Revealing a Higher Impact of Fascia Stimulation

“…Since ultrasound guided injections into fascia or muscle are useful for testing their sensitivity, this assumption may be tested by comparing chemically induced pain intensity levels and elicited pain distribution patterns for fascia and muscle input in healthy subjects with those of clinical low back pain patients. Furthermore, it has been shown that the innervation density within several fasciae can differ [ 33 ] as well as their central efficacy after hypertonic saline stimulation [ 7 ]. Thus, further studies are needed to investigate differences in pain behavior within the fascia network.…”

Potential Nociceptive Role of the Thoracolumbar Fascia: A Scope Review Involving In Vivo and Ex Vivo Studies

“…A total of seven studies characterized the distribution of the nociceptive nerve fibers terminating within the TLF [39,50,[55][56][57][58][59]. All these studies investigated whether fasciae associated with muscle are also innervated by peptidergic nociceptive sensory fibers.…”

Molecular Mechanisms Underlying the Pain-Relieving Effects of Extracorporeal Shock Wave Therapy: A Focus on Fascia Nociceptors

“…Nonetheless, data were collected from different parts of the thoracolumbar fascia (TLF), either small areas of the fascia lateral to the spinous processes or more lateral areas of the TLF. Specific differences in density innervation and types of fibers occur depending on the fascial area [ 59 , 95 ]. This, in turn, may explain the discrepancies in literature data [ 91 , 95 ].…”

“…In this regard, it is worthy of mentioning that compared to the underlying muscles, the fascial tissue shows a greater innervation with multiple sensory nerve fibers including those with nociceptive capability [ 57 , 58 , 59 ]. Thus, the fascial system is recently, though gradually, emerging as a major contributor in the pathogenesis of musculoskeletal pain and dysfunctions including MPS [ 58 , 60 , 61 , 62 , 63 , 64 ].…”