This focus has been reinforced by our time spent in the anatomy lab, in conjunction with the study of drawings in traditional anatomy texts. But have traditional dissection approaches provided accurate representations of human anatomy?
These images, formed using the sharp blade of a scalpel coupled with the resolve of the anatomist to demonstrate predetermined structures, have failed to demonstrate the continuity of the tissues making up the human form. As such, many therapeutic techniques have been developed using this perspective that focus on “tight muscles,” or skeletal alignment/movement alone. However, these anatomical representations are far removed from the reality of the intricate human system. Fascia has long been considered a nuisance in anatomical procedure hindering the visualization of the “important” underlying tissues. However, it is this connective tissue that actually defines and maintains our bodies’ contour and shape. More recent literature has also demonstrated its importance for human movement, force transmission, proprioception and kinesthetic awareness. As noted by van der Wal (2009), the architecture of the connective tissue “is more important for understanding functional meaning than is more traditional anatomy, the anatomical dissection method of which neglects and denies the continuity of the connective tissue as an integrating matrix of the body.”
Research has also revealed the probable link of this system with numerous injuries and pathologies. This article intends to simply act as a brief introduction to fascia (as there are now numerous articles detailing the specifics of this fascinating tissue) with the purpose of drawing the attention of the manual practitioner to the changing target of soft-tissue treatment interventions.
Fascia is found throughout the body and wraps around every cell, tissue, organ and system. As is often noted, if it were possible to remove all other tissues, organs and systems in the body (even the nervous system) but leave behind the intricate network of connective tissue, the basic human body shape and form would not be dramatically altered. Thus, fascia spreads throughout the body in a three-dimensional web from head to foot without interruption, forming a full-body continuity.
The complexity of fascial tissue can be simplified into three divisions: fascia superficialis (superficial layer), fascia profunda (middle layer) and deepest fascia (deepest layer). Since fascia is a contiguous interconnected soft tissue, each layer smoothly transitions from one layer to the next. Thus there is no “clear” division between layers.
|Figure 1: Reflected superficial fascia with yellow adipose deposits and its relationship with the underlying profunda layer (with kind permission from GilHedley.com).
This is a layer of loose connective tissue intimately located beneath the dermis of the skin and is often described as “subcutaneous tissue” due to the visualization, during human dissection, of bright yellow adipose deposits filling the latticework created by the pale-coloured fascia. This layer anchors the skin onto the underlying profunda layer (myofascia).
|Figure 2: Outer fascia profunda surrounding a muscle bundle (with kind permission from GilHedley.com).
Located deep to, but intimately interconnected with, the fascia superficialis, is the profunda layer, which is composed of a denser fibrous connective tissue with little fat present. This layer invests various internal structures, including the muscles, where it forms the encasing epimysium (surrounding whole muscles), perimysium (surrounding muscular bundles) and endomysium (surrounding individual muscle fibres).
This layer is also known as the “dural tube.” This fascia surrounds and protects central nervous system structures, including the brain and spinal cord.
Movement and interconnectivity
Though fascia is separated into layers, fascia continuity has been shown both experimentally and clinically throughout the body. The complexity of the relationships between layers (or fascial planes) is heightened by the necessity for each layer to maintain a degree of relative, or independent, motion.
The primary function of the fascia superficialis layer is to encase, support, shape and protect the underlying tissue. Although the fascia superficialis and fascia profunda are extensively connected by microfilaments, recent literature has noted the need for mobility of this superficial tissue, which allows the relatively independent movement of the skin and the muscles, important for normal muscle functions, and unrestrained joint movements. Seemingly contrary to this, damage to the subcutaneous connective tissue can lead to adhesion between it and underlying tissue, which may deteriorate muscle function and hinder joint motion. (I refer to the movement of the fascia superficialis over the underlying profunda layer “Inter-Layer Sliding.”)
The fascia profunda layer is often assumed to include only the collagenous connective tissue that overlies the muscular system. However, as noted above, this layer is actually segregated into several investing layers: epimysium, perimysium and endomysium. Thus this layer is inclusive of all connective tissues encapsulating groups of muscles, individual muscles, muscle fibres, and muscle fibrils. McCombe and colleagues (2001) showed that the structurally defined interface of fascia and muscle tissue creates an effective plane for sliding motion.
|Figure 3: Assessment of Inter-Layer Sliding using the Tissue Tension Technique, the method used in the Functional Range Release™ soft-tissue management system.
Thus relative motion between the layers, or lack thereof, resulting from increased amounts of fascial fibrosis must be considered when assessing soft-tissue symptoms and function.
TISSUE RESPONSES AND A CHANGING APPROACH
As previously noted, historically, soft-tissue techniques have focused primarily on the treatment of muscular tissue by means of soft-tissue manipulation and/or stretching. However, when considering the physical make-up of muscle tissue, it is simply composed of contractile proteins (i.e., actin, myosin, etc.) situated in a series, grouped into bundles. Each fibre, bundle and muscle is encased by fascia. The goal of soft-tissue therapies has never been to tear muscle proteins apart. It has been to remove restrictive scar tissue, or fibrosis. But where does this fibrosis form? Here is a list of the various processes that are known to follow soft-tissue injury:
- Remodelling of connective tissue with lower tensile stiffness and lower ultimate strength;
- Randomized collagen fibre direction and deposition (i.e., fibrosis);
- Inability of collagen bundles to slide easily past one another due to cross-linking;
- Substitution of collagen types with those of lesser strength.
You might be wondering why the intended tissue makes a difference? It would be easy to assume that the soft-tissue therapies currently being utilized have been working on the fascia all along. However, this assumption is incorrect. This is because the research that has been performed on this amazing tissue demonstrates that it does not respond in the same manner as muscular tissue. Thus many changes in soft-tissue application must be made in order to expect permanent, favourable changes in fascial structure with soft-tissue application.
Although it would be out of the scope of this article to review all of the literature concerning the responses of fascial tissue to load application, we can generalize that it seems the application of the load must be delivered for much longer periods than many current treatment approaches afford. As such, new treatment approaches have been created to incorporate all that is known regarding the responses of fascial tissue.*
The current research available on fascia has demonstrated the significance of this tissue in various body functions, not the least of which is its effect on movement and biomechanics. It has also demonstrated that injury can lead to alterations of fascial tissue, which can significantly hinder movement and contribute to the development of pain symptoms. New techniques of soft-tissue application have been specifically developed based on this research in order to effect favourable changes in fascia composition and mechanics. However, as always, further clinical and scientific research needs to be done to confirm and support the concepts presented.
*One such treatment approach, Functional Range Release™, a system created by the author, was developed in the context of the current literature available on this important tissue.
- van der Wal, J. The Architecture of the Connective Tissue in the Musculoskeletal System – An Often Overlooked Functional Parameter as to Proprioception in the Locomotor Apparatus. International Journal of Therapeutic Massage and Bodywork 2009; 2(4):1-15.
- Kawamata, S, Ozawa, J, Hashimoto, M, Kurose, T, and Shinohara, H. Structure of the rat subcutaneous connective tissue in relation to its sliding mechanism. Archives of Histology & Cytology 2003; 66(3):273-279.
- McCombe, D, Brown, T, Slavin, J, and Morrison, WA The histochemical structure of the deep fascia and its structural response to surgery. Journal of Hand Surgery, British and European Volume 2001; 26B(2):89-97.
- Wilson, IF, Schubert, W, and Benjamin, CI. The distally based radial forearm fascia-fat flap for treatment of recurrent de Quervain’s tendonitis. Journal of Hand Surgery 2001; 26:506-509.
- Kragh, JF, Jr., Svoboda, SJ, Wenke, JC, Brooks, DE, Bice, TG, and Walters, TJ. The role of epimysium in suturing skeletal muscle lacerations. Journal of the American College of Surgeons 2005; 200:38-44.
- Humphreys BK, Nevin S, Hubbard BB. Investigation of connective tissue attachments to the cervical spinal dura mater. Clin Anat 2003;16(2):152-9.