Myofascial Chains
Human anatomy representations typically depict skeletal muscles as separate entities, each with distinct origins and insertions. However, recent studies contest this view, proposing a widespread structural connection between muscles and collagen-rich connective tissues. On a microscopic level, muscle fibers are closely integrated with their endomysium throughout their entire peripheral length. Examining muscles from a macroscopic standpoint reveals a similar pattern, with muscles closely interwoven with surrounding fascia.
The concept of myofascial continuity extends beyond individual muscles and their associated connective tissues. Wilke et al. (2016) conducted a systematic review, analyzing data from 62 cadaver studies, to determine if neighboring muscles are also morphologically linked. The findings suggest strong evidence of continuity in most cases examined. For example, various soft tissues create a continuous pathway from the toes to the occipital bone on the body's dorsal side. This pathway includes fibers of the plantar aponeurosis fusing with the Achilles tendon, which then connects to the gastrocnemius and its fascia. A fascial band connects the calf muscles to the hamstrings at the knee joint, which subsequently attach to the lumbar fascia and the erector spinae muscle via the sacrotuberous ligament. These and other widespread tissue connections, like those on the lateral side, are referred to as "myofascial chains."
A defining characteristic of myofascial chains is the arrangement of components according to muscle fiber direction and lines of pull, contrasting with tissue continuity between parallel muscles (e.g., tibialis anterior and extensor digitorum longus). This arrangement allows for the transfer of greater force. Experimental research on cadavers and in vivo studies support this hypothesis, demonstrating significant interactions between myofascial chain components. Consequently, some researchers believe these chains may be involved in various musculoskeletal disorders.
The properties of fascia – its continuity, tensile strength, viscoelasticity, and adaptability – make it the ideal candidate for the continuous tensional element in the macroscopic biotensegrity model. The inherent pre-stress within the fascial network is considered crucial for maintaining the stability and responsiveness of the entire musculoskeletal system. Injuries or chronic adaptations leading to fascial thickening, adhesions, or tears represent disruptions in this tensional continuity, compromising the structural integrity and efficient function of the biotensegral system. The dynamic cellular activity within fascia, involving fibroblasts, fasciacytes, and potentially myofibroblasts, underscores its capacity for adaptation and remodeling, providing the biological basis for therapies aimed at restoring its normal structure and function.
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