Myofascial junction: Emerging insights into the connection between deep/muscular fascia and muscle.

Muscles and fasciae are mutually connected and are influenced by force transmission. However, the anatomical connectivity and histological features of these structures remain unclear. The aim of this study was to assess the evidence for connection between muscles and deep/muscular fasciae. We assessed this relationship in different topographical regions of human cadavers and in mice. The results showed that myofascial junctions (MFJ) were made up of collagen I immune-positive structures occupying an average area of 5.11 ± 0.81 µm2, distributed in discrete regions at the interface between muscle and fascia with an average density of 9.7 ± 2.51 MFJ/mm and an average inclination angle of 35.25 ± 1.52°. These specialized structures also showed collagen III and HA immunopositivity and the presence of elastic fibers. The human myofascial junction can be visualized, opening emerging insights into the connection between deep/muscular fascia and muscle.

Glisson's capsule matrix structure and function is altered in patients with cirrhosis irrespective of aetiology.

Background & Aims: Glisson's capsule is the interstitial connective tissue that surrounds the liver. As part of its normal physiology, it withstands significant daily changes in liver size. The pathophysiology of the capsule in disease is not well understood. The aim of this study was to characterise the changes in capsule matrix, cellular composition, and mechanical properties that occur in liver disease and to determine whether these correlate with disease severity or aetiology. Methods: Samples from ten control patients, and six with steatosis, seven with moderate fibrosis, and 37 with cirrhosis were collected from autopsies, intraoperative biopsies, and liver explants. Matrix proteins and cell markers were assessed by staining and second harmonic generation imaging. Mechanical tensile testing was performed on a test frame. Results: Capsule thickness was significantly increased in cirrhotic samples compared with normal controls irrespective of disease aetiology (70.12 ± 14.16 µm and 231.58 ± 21.82 µm, respectively), whereas steatosis and moderate fibrosis had no effect on thickness (90.91 ± 11.40 µm). Changes in cirrhosis included an increase in cell number (fibroblasts, vascular cells, infiltrating immune cells, and biliary epithelial cells). Key matrix components (collagens 1 and 3, hyaluronan, versican, and elastin) were all deposited in the lower capsule, although only the relative amounts per area of hyaluronan and versican were increased. Organisational features, including crimping and alignment of collagen fibres, were also altered in cirrhosis. Unexpectedly, capsules from cirrhotic livers had decreased resistance to loading compared with controls. Conclusions: The liver capsule, similar to the parenchyma, is an active site of disease, demonstrating changes in matrix and cell composition as well as mechanical properties. Impact and implications: We assessed the changes in composition and response to stretching of the liver outer sheath, the capsule, in human liver disease. We found an increase in key structural components and numbers of cells as well as a change in matrix organisation of the capsule during the later stages of disease. This allows the diseased capsule to stretch more under any given force, suggesting that it is less stiff than healthy tissue.

Detection of Mast Cells in Human Superficial Fascia.

The recent findings showed that the superficial fascia is a fibrous layer in the middle of hypodermis, richly innervated and vascularized, and more complex than so far demonstrated. This study showed the presence of mast cells in the superficial fascia of the human abdomen wall of three adult volunteer patients (mean age 42 ± 4 years; 2 females, 1 male), by Toluidine Blue and Safranin-O stains and Transmission Electron Microscopy. Mast cells are distributed among the collagen bundles and the elastic fibers, near the vessels and close to the nerves supplying the tissue, with an average density of 20.4 ± 9.4/mm2. The demonstration of the presence of mast cells in the human superficial fascia highlights the possible involvement of the tissue in the inflammatory process, and in tissue healing and regeneration processes. A clear knowledge of this anatomical structure of the hypodermis is fundamental for a good comprehension of some fascial dysfunctions and for a better-targeted clinical practice.

Detection of Lymphatic Vessels in the Superficial Fascia of the Abdomen.

Recently, the superficial fascia has been recognized as a specific anatomical structure between the two adipose layers-the superficial adipose tissue (SAT) and the deep adipose tissue (DAT). The evaluation of specific characteristics of cells, fibers, blood circulation, and innervation has shown that the superficial fascia has a clear and distinct anatomical identity, but knowledge about lymphatic vessels in relation to the superficial fascia has not been described. The aim of this study was to evaluate the presence of lymphatic vessels in the hypodermis, with a specific focus on the superficial fascia and in relation to the layered subdivision of the subcutaneous tissue into SAT and DAT. Tissue specimens were harvested from three adult volunteer patients during abdominoplasty and stained with D2-40 antibody for the lymphatic endothelium. In the papillary dermis, a huge presence of lymphatic vessels was highlighted, parallel to the skin surface and embedded in the loose connective tissue. In the superficial adipose tissue, thin lymphatic vessels (mean diameter of 11.6 ± 7.71 µm) were found, close to the fibrous septa connecting the dermis to the deeper layers. The deep adipose tissue showed a comparable overall content of lymphatic vessels with respect to the superficial layer; they followed the blood vessel and had a larger diameter. In the superficial fascia, the lymphatic vessels showed higher density and a larger diameter, in both the longitudinal and transverse directions along the fibers, as well as vessels that intertwined with one another, forming a rich network of vessels. This study demonstrated a different distribution of the lymphatic vessels in the various subcutaneous layers, especially in the superficial fascia, and the demonstration of the variable gauge of the vessels leads us to believe that they play different functional roles in the collection and transport of interstitial fluid-important factors in various surgical and rehabilitation fields.

From Muscle to the Myofascial Unit: Current Evidence and Future Perspectives.

The "motor unit" or the "muscle" has long been considered the quantal element in the control of movement. However, in recent years new research has proved the strong interaction between muscle fibers and intramuscular connective tissue, and between muscles and fasciae, suggesting that the muscles can no longer be considered the only elements that organize movement. In addition, innervation and vascularization of muscle is strongly connected with intramuscular connective tissue. This awareness induced Luigi Stecco, in 2002, to create a new term, the "myofascial unit", to describe the bilateral dependent relationship, both anatomical and functional, that occurs between fascia, muscle and accessory elements. The aim of this narrative review is to understand the scientific support for this new term, and whether it is actually correct to consider the myofascial unit the physiological basic element for peripheral motor control.

Blood supply to the superficial fascia of the abdomen: An anatomical study.

The aim of this study was to examine data demonstrating that Scarpa's fascia, a superficial fascia of the anterior abdominal wall, is a vascularized tissue. Specimens of the fascia of seven volunteers undergoing abdominoplasty surgical procedures at the Plastic Surgery Unit of the University of Padova Medical Center were collected. Fractal analysis and quantitative assessment of the vascular network of the fascia was carried out, exploiting the presence of blood in the vessels. Each sample was divided and processed for histological/immunohistochemical analysis (into 5 micron-paraffin embedded sections and cryo-sectioned free-floating samples) as well as for electron microscopy study. A rich vascular pattern forming a fine, dense meshwork with an area percentage of 6.20% ± 2.10% von Willebrand factor stained vessels was noted in all the specimens of the fascia examined; the area percentage of the αSMA-stained vessels was 2.93% ± 1.80%. The diameters of the vessels fell between the 13 and 65 µm range; the network was composed of arteries, veins, capillaries and lymphatic segments. Topological results showed that the vascular network within Scarpa's fascia is well branched (segments: 6615 ± 3070 and 8.40 ± 3.40 per mm2 ; crossing points: 3092 ± 1490 and 3.40 ± 1.90 per mm2 ). Fractal analysis (fractal dimension = 1.063 ± 0.10; lacunarity = 0.60 ± 0.10) revealed that this particular vascular network has an optimal spatial distribution and homogeneity occupying the entire space of the superficial fascia. These findings could undoubtedly be useful to plastic surgeons as well as to pain management specialists.

Urinary Incontinence and Other Pelvic Floor Dysfunctions as Underestimated Problems in People under Forty Years: What Is Their Relationship with Sport?

Urinary incontinence is still an underestimated problem due to its anatomical complexity and social taboo. Most of the time, it is believed to affect predominantly the elderly female population, and the literature still lacks data on its presence in the younger and male populations. Its relationship with other pelvic floor dysfunctions (PFDs) and sport activity remains an open topic. Thus, the present study surveyed 342 subjects of both genders, ranging from 18 to 39 y/o and with different sport activity levels, to understand the prevalence of PFDs (such as haemorrhoids, anal fissures, involuntary urinary/faecal leakage, and urgency). The results also showed a significative prevalence in younger, sporty, and male people. Approximately one third of the population had urinary incontinence mostly during stress activities (sport activity: 17%, cough/sneeze: 13%). The statistical analysis confirmed a higher prevalence in the cases of a light (32%) and intense (41%) sport activity level and a protective role of sport if practiced between 5 and 10 h/week, with bodybuilding/CrossFit and running seeming to be the riskiest sports. The relationship with the other PFDs showed a statistically significant dependence with most of them, confirming that urinary incontinence cannot be considered a separate problem from the other PFDs.

The Effects of Aging on the Intramuscular Connective Tissue.

The intramuscular connective tissue plays a critical role in maintaining the structural integrity of the muscle and in providing mechanical support. The current study investigates age-related changes that may contribute to passive stiffness and functional impairment of skeletal muscles. Variations in the extracellular matrix in human quadriceps femoris muscles in 10 young men, 12 elderly males and 16 elderly females, and in the hindlimb muscles of 6 week old, 8 month old and 2 year old C57BL/6J male mice, were evaluated. Picrosirius red, Alcian blue and Weigert Van Gieson stainings were performed to evaluate collagen, glycosamynoglycans and elastic fibers. Immunohistochemistry analyses were carried out to assess collagen I, collagen III and hyaluronan. The percentage area of collagen was significantly higher with aging (p < 0.01 in humans, p < 0.001 in mice), mainly due to an increase in collagen I, with no differences in collagen III (p > 0.05). The percentage area of elastic fibers in the perimysium was significantly lower (p < 0.01) in elderly men, together with a significant decrease in hyaluronan content both in humans and in mice. No significant differences were detected according to gender. The accumulation of collagen I and the lower levels of hyaluronan and elastic fibers with aging could cause a stiffening of the muscles and a reduction of their adaptability.

Innervation of human superficial fascia.

The superficial fascia has only recently been recognized as a specific anatomical structure. Furthermore, whereas it is actually recognized that the innervation of the deep/muscular fascia plays a key role in proprioception and nociception, there are very few studies that have analyzed these characteristics in the superficial fascia. In this work, our group analyzed two different anatomical districts (abdomen and thigh), from volunteer patients, undergoing surgery procedures. Each sample was processed for histological analysis by Hematoxylin&Eosin, and by immunohistochemistry stainings (in 5-micron-paraffin embedded section and in cryosectioned free floating samples), with antibodies specific for nerve fibers: S100 antibody for myelinating and non-myelinating Schwann cells, PGP9.5 antibody as pan-neuronal marker, tyrosine hydroxylase for autonomic innervation. The results revealed a huge innervation: the nervous structures were found above all around blood vessels and close to adipocytes, but they penetrated also in the connective tissue itself and are found in the midst of fibro-adipose tissue. The tissue is pervaded by both thin (mean diameter of 4.8 ± 2.6 µm) and large nerve fiber bundles of greater diameter (21.1 ± 12.2 µm). The ratio S100/TH positivity was equal to 2.96, with a relative percentage of autonomic innervation with of 33.82%. In the light of these findings is evident that the superficial fasciae have a clear and distinct anatomical identity and a specific innervation, which should be considered to better understand their role in thermoregulation, exteroception and pain perception. The knowledge of the superficial fascia may improve grading and developing of different manual approach for treatments of fascial dysfunctions, and the understanding of how some factors like temperature or manual therapies can have an impact on sensitivity of the fascia.

Immediate Effects of Extracorporeal Shock Wave Therapy in Fascial Fibroblasts: An In Vitro Study.

Extracorporeal shock waves (ESWs) are used in the treatment of soft tissue injuries, but their role in the treatment of myofascial pain has not yet been demonstrated. The aim of this study was to investigate changes in cell biology of fibroblasts derived from deep/muscular fascia following treatment with ESWs. Primary fascial fibroblasts were collected from small samples of human fascia lata of the thigh of three volunteer patients (two men, one woman) during orthopedic surgery, and put in culture. These cells were exposed to 100 impulses of 0.05 mJ/mm2 with a frequency of 2.5 Hz, using 3D-printed support. This study demonstrated for the first time that ESWs can lead to in vitro production of hyaluronan-rich vesicles immediately after the treatment. At 1, 4, and 24 h after treatment, Alcian blue and Toluidine blue staining; immunocytochemistry to detect hyaluronic acid binding protein (HABP), collagen I, and collagen III; and transmission electron microscopy demonstrated that these vesicles are rich in hyaluronan and collagen I and III. The diameter of these vesicles was assessed, highlighting a small size at 1 h after ESW treatment, whereas at 4 and 24 h, they had an increase in the size. Particularly evident was the release of hyaluronan-rich vesicles, collagen-I, and collagen-III starting at 1 h, with an increase at 4 h and maintenance by 24 h. These in vitro data indicate that fascial cells respond to ESW treatment by regulating and remodeling the formation of extracellular matrix.

Fascial Innervation: A Systematic Review of the Literature.

Currently, myofascial pain has become one of the main problems in healthcare systems. Research into its causes and the structures related to it may help to improve its management. Until some years ago, all the studies were focused on muscle alterations, as trigger points, but recently, fasciae are starting to be considered a new, possible source of pain. This systematic review has been conducted for the purpose of analyze the current evidence of the muscular/deep fasciae innervation from a histological and/or immunohistochemical point of view. A literature search published between 2000 and 2021 was made in PubMed and Google Scholar. Search terms included a combination of fascia, innervation, immunohistochemical, and different immunohistochemical markers. Of the 23 total studies included in the review, five studies were performed in rats, four in mice, two in horses, ten in humans, and two in both humans and rats. There were a great variety of immunohistochemical markers used to detect the innervation of the fasciae; the most used were Protein Gene Marker 9.5 (used in twelve studies), Calcitonin Gene-Related Peptide (ten studies), S100 (ten studies), substance P (seven studies), and tyrosine hydroxylase (six studies). Various areas have been studied, with the thoracolumbar fascia being the most observed. Besides, the papers highlighted diversity in the density and type of innervation in the various fasciae, going from free nerve endings to Pacini and Ruffini corpuscles. Finally, it has been observed that the innervation is increased in the pathological fasciae. From this review, it is evident that fasciae are well innerved, their innervation have a particular distribution and precise localization and is composed especially by proprioceptors and nociceptors, the latter being more numerous in pathological situations. This could contribute to a better comprehension and management of pain.

Fetal Fascial Reinforcement Development: From "a White Tablet" to a Sculpted Precise Organization by Movement.

Fasciae have received much attention in recent years due to their important role in proprioception and muscular force transmission, but few studies have focused on fetal fasciae development and there is no study on the retinacula. The latter are fascial reinforcements that play a key role in proprioception and motor coordination. Furthermore, it is still unclear if they are genetically determined or if they are defined by movements, and if they are present during gestation or if they appear only later in the childhood. We aim to identify their structural organization by qualitative and quantitative assessments to establish their role the myofascial development, highlighting their appearance and organization. Samples from the wrist retinacula, posterior forearm, ankle retinacula, anterior leg, iliotibial tract and anterior thigh of six fetus body donors (from 24th to 40th week of gestation) and histological sections were obtained and a gross anatomy dissection was performed. Sections were stained with hematoxylin-eosin to observe their overall structure and measure their thicknesses. Using Weigert Van Gieson, Alcian blue and immunostaining to detect Hyaluronic Acid Binding Protein (HABP), Collagens I and III (Col I and III) were realized to assess the presence of elastic fibers and hyaluronan. This study confirms that the deep fasciae initially do not have organized layers and it is not possible to highlight any reinforcement. The fascial development is different according to the various area: while the deep fascia and the iliotibial tract is already evident by the 27th week, the retinacula begin to be defined only at the end of pregnancy, and their complete maturation will probably be reached only after birth. These findings suggest that the movement models the retinacula, structuring the fascial system, in particular at the end of pregnancy and in the first months of life. The fasciae can be imagined, initially, as "white tablets" composed of few elastic fibers, abundant collagens and HA, on which various forces, u movements, loads and gravity, "write their history".

Are Patellofemoral Ligaments and Retinacula Distinct Structures of the Knee Joint? An Anatomic, Histological and Magnetic Resonance Imaging Study.

There is disagreement regarding the description of the patellofemoral ligaments (PFLs), considered by some authors as capsular thickening and by others as independent ligaments. It was hypothesised that the PFLs and retinacula are structures with different histological features. The aim of this study was to describe the stabilising structures of the patella in detail and to determine if the PFLs and retinacula are different and separable structures from a macroscopic, microscopic and imaging viewpoint. An anatomical study was performed on eight knees from five cadavers (mean age, 56.2 years; range, 35-63 years), and a histological study was conducted on specimens from nine patients having a mean age of 65 years (range 35-84 years) who had undergone surgical knee procedures. The imaging study was based on 100 MRIs (96 patients). The mean age was 46 years (range 16-88), and the study analysed the capsular-ligamentous structures. In the medial compartment, the layers and structures were as follows: superficial layer, medial retinaculum; intermediate layer, Medial Collateral Ligament (MCL), Posterior Oblique Ligament (POL) and Medial Patellofemoral Ligament (MPFL); deep layer, deep part of the MCL and joint capsule. In the lateral compartment, the layers and structures were the following: superficial layer, lateral retinaculum; intermediate layer, Lateral Collateral Ligament (LCL) and Lateral Patellofemoral Ligament (LPFL); deep layer, joint capsule. All of the knees examined presented a clearly distinguishable MPFL and LPFL separable from the capsular layer. Histological study: there was a higher density of nerve fibres in retinacula compared to ligaments (p = 0.0034) and a higher content of elastic fibres in retinacula (p < 0.0005). In imaging, there was no difference between medial and lateral retinaculum thickness (p > 0.05). In conclusion, both the lateral and medial compartment can be described using the three-layer scheme. PFLs and retinacula are separate structures both macroscopically and according to imaging analysis. The retinacula respond to their specific function with a higher nerve fibre content and higher number of elastic fibres compared to the ligaments.

Elastic Fibres in the subcutaneous tissue: Is there a difference between superficial and muscular fascia? A cadaver study.

BACKGROUND: In last years the role of fascia in proprioception and pain has been confirmed in numerous papers, but the real structure of fasciae is not still entirely known. To date, many studies have evaluated the elastic fibres in arteries, ligaments, lungs, epidermis and dermis, but only two studies exist about the elastic fibres in the fasciae, and they did not distinguish between superficial (in the subcutaneous tissue) and deep/muscular fasciae. The aim of the study was to assess the percentage of elastic fibres between superficial and deep fascia. MATERIALS AND METHODS: Three full thickness specimens (proximal, middle and distal respectively) were taken from each of four regions of the thigh of three non-embalmed cadavers: the anterior (Ant), the lateral (Lat), the posterior (Post) and the medial (Med) aspect. Thus, a total of 12 specimens were collected from each analysed thigh and histological Weigert Van Gieson stains was performed. Three sections per specimen were considered for the morphometric analysis. RESULTS: In all the specimens the superficial and deep fasciae were clearly recognizable. The difference in percentage of elastic fibres between superficial and deep fasciae in same region for all four was highly significant (p < 0.001). They are abundant in the superficial fascia than deep fascia. CONCLUSIONS: In the light of these findings is evident that the superficial (in the subcutaneous tissue) and deep fasciae have different elasticity. This difference may improve grading of fascial dysfunction in dermatological diseases as burns, scars and lymphedema to better plan treatments.

Ultrasound Imaging of Brachial and Antebrachial Fasciae.

Knowledge about fasciae has become increasingly relevant in connection to regional anesthesiology, given the growing interest in fascial plane, interfascial, and nerve blocks. Ultrasound (US) imaging, thanks to high definition, provides the possibility to visualize and measure their thickness. The purpose of this study was to measure and compare, by US imaging, the thickness of deep/muscular fasciae in different points of the arm and forearm. An observational study has been performed using US imaging to measure brachial and antebrachial fasciae thickness at anterior and posterior regions, respectively, of the arm and forearm at different levels with a new protocol in a sample of 25 healthy volunteers. Results of fascial thickness revealed statistically significant differences (p < 0.0001) in the brachial fascia between the anterior and the posterior regions; in terms of the antebrachial fascia, no statistically significant difference was present (p > 0.05) between the regions/levels. Moreover, regarding the posterior region/levels, the brachial fascia had a greater thickness (mean 0.81 ± 0.20 mm) than the antebrachial fascia (mean 0.71 ± 0.20 mm); regarding the anterior region/levels, the antebrachial fascia was thicker (mean 0.70 ± 0.2 mm) than the brachial fascia (mean 0.61 ± 0.11 mm). In addition, the intra-rater reliability reported good reliability (ICC2,k: 0.88). US imaging helps to improve grading of fascial dysfunction or disease by revealing subclinical lesions, clinically invisible fascial changes, and one of the US parameters to reliably evaluate is the thickness in the different regions and levels.

Fascia Lata Alterations in Hip Osteoarthritis: An Observational Cross-Sectional Study.

The present study compares the structure and composition of fascia lata in healthy subjects and in patients with hip osteoarthritis (OA), to evaluate any differences in the amount of Collagen type I, Collagen type III, and Hyaluronan. Fascia lata samples from voluntary healthy subjects and patients with OA were harvested during surgery. Collagen type I (COL I), III (COL III) antibody, and biotinylated hyaluronan binding protein (HABP) immunohistochemistry stainings were used to evaluate fascial morphology and COL I, COL III, and Hyaluronan (HA) content in both groups. Ten samples from healthy subjects and 11 samples from OA patients were collected. COL I was significantly more abundant in the OA group (p = 0.0015), with a median percentage positivity of 75.2 (IQR 13.11)%, while representing only 67 (IQR: 8.71)% in control cases. COL III, with median values of 9.5 (IQR 3.63)% (OA group) and 17.10 (IQR 11)% (control cases), respectively, showed significant reduction in OA patients (p = 0.002). HA showed a median value of 10.01 (IQR 8.11)% in OA patients, denoting significant decrease (p < 0.0001) with respect to the control group median 39.31 (IQR 5.62)%. The observed differences suggest a relationship between fascial pathology and hip OA. The observed increase in COL I in OA patients, along with the reduction of COL III and HA, could lead to fascial stiffening, which could alter fascial mechanics and be linked to the development and symptoms of OA.

Pilot Study of Sacroiliac Joint Dysfunction Treated with a Single Session of Fascial Manipulation® Method: Clinical Implications for Effective Pain Reduction.

Background and Objectives: Sacroiliac joint dysfunction (SIJD) generally refers to pain in the lower back due to abnormal sacroiliac joint movement, either from hypomobility or hypermobility. It is considered to be the principal cause in up to 40% of low back pain cases. In literature, it emerges that the "fascia", by its anatomical continuity, if altered or densified in different regions of the body with respect to the sacroiliac joint and its surroundings, may have a fundamental role in the genesis of SIJD and low back pain. The purpose of the present study is to evaluate the effectiveness of incorporating a single session of Fascial Manipulation®-Stecco method®, treating the muscular fasciae at distance from the painful region. Materials and Methods: Twenty patients with acute and chronic sacroiliac joint dysfunction (SIJD) were recruited (16 males and 4 females, mean age of 46.6 ± 12.98 years). Patients underwent a predefined assessment protocol, followed by an evaluation of myofascial pain and subsequent manipulation of the fascia at points at least 20 cm away from the posterior inferior iliac spines (PIIS). Each patient underwent three pain evaluations: pre-treatment (t0), post-treatment (t1), and at a 1-month follow-up (t2). For the evaluation in t0, t1 the numerical rating scale (NRS) for the intensity of pain and the algometer for the pain threshold at the PIIS were used; in t2 only the NRS scale. Results: The results obtained by comparing the algometer measurements with the NRS values between t0 and t1 were in both cases statistically significant (p < 0.0001), whereas the comparison between the NRS values at t1 and at t2 was not statistically significant (p > 0.05). Conclusions: A single Fascial Manipulation treatment, even when applied at least 20 cm from the PIIS, can potentially decrease pain around the SIJ. The inclusion of this type of approach in SIJD can allow for improved patient management, better tolerance for other treatments and a more rapid application of pain-free exercise programs.

Diabetic Foot: The Role of Fasciae, a Narrative Review.

Wound healing is an intricate, dynamic process, in which various elements such as hyperglycemia, neuropathy, blood supply, matrix turnover, wound contraction, and the microbiome all have a role in this "out of tune" diabetic complex symphony, particularly noticeable in the complications of diabetic foot. Recently it was demonstrated that the fasciae have a crucial role in proprioception, muscular force transmission, skin vascularization and tropism, and wound healing. Indeed, the fasciae are a dynamic multifaceted meshwork of connective tissue comprised of diverse cells settled down in the extracellular matrix and nervous fibers; each constituent plays a particular role in the fasciae adapting in various ways to the diverse stimuli. This review intends to deepen the discussion on the possible fascial role in diabetic wounds. In diabetes, the thickening of collagen, the fragmentation of elastic fibers, and the changes in glycosaminoglycans, in particular hyaluronan, leads to changes in the stiffness, gliding, and the distribution of force transmission in the fasciae, with cascading repercussions at the cellular and molecular levels, consequently feeding a vicious pathophysiological circle. A clear scientific perception of fascial role from microscopic and macroscopic points of view can facilitate the identification of appropriate treatment strategies for wounds in diabetes and create new perspectives of treatment.

Evidence of a new hidden neural network into deep fasciae.

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.