yogabook / movement physiology / fasciae
Fasciae
Fasciae are connective tissue: somewhat elastic sheathing of individual organs, muscles (entire heads as well as within these between all subdivisions such as fibers and fiber bundles) or muscle groups, made up of crossed collagen fibers and elastic nets; fasciae are generally purely passive, not contractile. Fibroblasts produce the collagen. At the ends of the muscles, the fasciae unite with the tendons. The fasciae of the muscles separate them from neighboring structures such as organs, skins, bones, but also from each other and enable the structures to slide over each other with little friction thanks to a lubricant produced by the fibroblasts and fibrocytes. Hardening and adhesion lead to discomfort. Fasciae can bind a lot of water and serve as a water reservoir. They contain phagocyte cells that act enzymatically against intruding substances. A distinction is made between
- superficial fasciae: loose fascial tissue in the subcutaneous tissue; they surround and connect organs, glands, neurovascular pathways and tissue;
Properties: water and fat storage, flexibility. It is assumed that these fasciae form a body-wide non-neural network. Extensibility: good - deep fasciae: surround all muscles, bones, joints, nerve tracts, blood vessels; form tendons, tendon plates (aponeuroses), ligaments, joint capsules, retinaculae, periosteum, perichondrium, tunica externa of the blood vessels and perineurium of the nerve tracts;
Propertise: they have mechano-, thermo- and chemosensors and nerve endings of the PNS. The endomysium envelops individual muscle fibers, the perimysium muscle fiber bundles and the epimysium the entire muscle. Elasticity: less good than the superficial fasciae - visceral fascia: suspension and embedding of the internal organs and the brain. This includes the meninges and pleura, peritoneum and pericardium.
Properties: There is a visceral layer directly on the organ and a parietal layer around it. Blood and lymph vessels run through the fasciae.
Prolonged tension and therefore too little movement in the fascia leads to the activation of fibrinogen in the lymphatic fluid, resulting in fibrin and therefore matted, sticky and less flexible fascia and pressure on the nerve endings. In patients with chronic back pain, a study showed an average 20% reduction in the flexibility of the fasciae. Fascial adhesions and hardening can account for a significant proportion of the soft-elastic range of motion. In severe cases, fascia can stick together to form inflexible blocks, from the superficial fascia right into the muscles. Fasciae also alter as a result of ageing and lack of exercise, losing water and becoming increasingly sticky and hard, which leads to further restrictions in flexibility and pain during movement. The effect of stress hormones also leads to overstressing of the fasciae, which is reversible in the short term but very difficult to reverse in chronic cases. If the adrenaline receptors of the myofibroblasts are stimulated, this leads to immunomodulation after 24 hours via the messenger substance TGF-beta and causes the fasciae to become more fibrotic. This points to a possible pathomechanism of fibromyalgia: weeks of unusually high stress seem to be a clear predisposition for its onset. Furthermore, the autonomic innervation of the superficial fascia is clearly altered in fibromyalgia.
Acidosis leads to hardening of the fascia and restriction of blood and lymph flow. Sensors of these fasciae:
- pain (nociceptors)
- changes in movement (proprioceptors)
- changes in pressure and vibrations (mechanoreceptors)
- changes in the chemical environment (chemoreceptors)
- temperature fluctuations (thermoreceptors).
Deep fasciae can react to chemical and mechanical stimulation by relaxing or contracting and remodeling themselves; they contain smooth muscle-like connective tissue cells (myofibroblasts) for long-term contraction. The higher the myofibroblast contraction, the stiffer the deep fascia (also in pathological events, see Dupuytren’s contracture, frozen shoulder).
In the thigh and lower leg, several muscles are combined with fascia to form lodges (compartments). A significant increase in pressure in the compartment leads to compartment syndrome, which may need to be relieved surgically. The cause may be functional (unusual muscular exertion with a massive increase in muscle volume) or traumatic. Other causes such as burns or ischemia can also lead to this.
With a total of approx. 250 million sensory cells, the fascia can be considered the largest sensory organ in terms of surface area and number of receptors, whereas the skin only contains approx. 100 million receptors.
Fasciae are usually also affected by injuries, with a significant, if not the majority, of damage occurring at their transition to the muscles. Sports-related strains are 80% collagenous ruptures of the fascia and not muscle fiber tears.
In animal experiments, a positive influence of stretching on the fibroblast scaffold has already been demonstrated: they can become many times larger, longer and flatter as a result. In cases of inflammation, e.g. in the thoracolumbar fascia, stretching releases anti-inflammatory substances and reduces inflammation. Stretching also promotes the release of cytokines (growth factors, immune and inflammatory mediators: interferons, interleukins, colony-stimulating factors, tumor necrosis factors and chemokines). It is assumed that resolvins released by stretching have a general anti-inflammatory effect, although it is doubted that the stretching effect of muscles in massages has a comparable effect. In general, athletes who stretch regularly (!) show better performance and a lower injury rate. Stretching also has an effect on arterial stiffness.
So, stretching has a positive effect. A lack of movement, in particular iatrogenic immobilization after trauma and fractures, leads to matted, thickened and chaotically structured fasciae, which is clearly evident after just 3 weeks of immobilization with a cast. This is usually associated with a certain degree of loss of function, and the pathologically altered fasciae of this type can also put pressure on muscles and nerves. In general, it must be assumed that today’s civilized level of movement is incompatible with the evolutionary outcome of the human body. According to Harvard paleoanthropologist Dan Lieberman, at least 150 minutes of exercise, preferably such as 30 minutes about 5 times a week with at least 50% increased heart rate, is recommended.