What is Fascia?
Hey Readers! I am so thankful that you are here! "Fascia" (pronounced "fash-uh") has become the buzz word in the fitness and human movement communities, but do you really know what it is? In this month's blog post, I will go over what fascia is, what is does, and how movement, or lack of, impacts your fascial system. So, stay with me because it's about to get FASCIA-nating.
What is Fascia?
Fascia is a ubiquitous, flexible and sturdy, silvery-white, soft tissue that acts as your body's seam system; it literally threads your tissues and organs to one another. Fascia surrounds, penetrates, and connects every muscle, bone, organ, blood vessel, and nerve. Your fascial system can be thought of as your soft-tissue skeleton, forming a whole-body, continuous, 3-D matrix of structural support. Everything inside of your body (your bones, muscles, organs, etc.) are essentially floating within this matrix of fibrous, interweaving fascia. Fascia is everywhere in the human body. Indeed, fascia is the most prevalent tissue in the human body. Your fascial system is also one of the earliest developing tissues in the human embryo, beginning to develop when an embryo contains only 50 cells.
Categories/Types of Fascia?
There are many different ways that anatomists categorize and classify fascia. In this post, I'll go over the four different types of fascia based on location in the body.
Superficial fascia, sometimes referred to as "loose connective tissue" is the fascial layer closest to the skin. This type of fascia is found directly underneath the layer of fat under the skin.
Deep fascia is more dense and more organized than superficial fascia, structurally speaking. Deep fascia covers, and connects, muscles and bones. In fact, all muscles in the human body are covered, interpenetrated, and connected to fascia. Because muscles and fascia are so tightly connected, they are often collectively referred to as "myofascia" (myo = muscle). Deep fascia also includes tendons (i.e. soft tissue that connects muscle-to-bone), which is depicted in the first image below. Ligaments (i.e. soft tissue that connects bone-to-bone) are also part of the deep fascia category, depicted in the second image below, which shows the ligaments that attach the femur (thigh bone) to the hip bone. Deep fascia also includes the membrane that wraps around bones, known as periosteum.
Meningeal fascia surrounds components of the nervous system, such as the brain, spinal cord, and individual neurons. This type of fascia helps to provide the nervous system with a certain degree of flexibility, movement potential, and support.
Visceral fascia surrounds the lungs, heart, and abdominal organs, supporting each organ within its cavity and affixing each organ to the body wall. Issues with visceral motility, for example from surgery or trauma, can result in scar tissue restrictions, which can negatively impact core trunk control, stability, and strength.
Components of Fascia - What is Fascia Made of?
Fascia is comprised of the following components: cells and nerve endings, fibers, and ground substance. Let's talk about each one of these.
The most abundant cell in fascia is known as a fibroblast, which essentially produces and maintains the entire structure of fascial tissue (see image below). Several different nerve endings and specialized sensory neurons are also located within fascia. For example, proprioceptors are highly prevalent in fascia, and these neuronal cells are responsible for sensing where the body is in space and how your body is moving. Nociceptors are also prevalent in fascia, and these specialized neurons are responsible for detecting pain. Other neurons include muscle spindles and golgi tendon organs, which are responsible for maintaining appropriate muscle tone (stay tuned for a future blog post that will dive deeper into these sensory neurons). The current line of thinking in fascial science is that your fascia might actually be your primary sensory organ since it is quite literally loaded with a variety of sensory neurons. Thus, keeping your fascia healthy, hydrated, and mobile is super important for your overall sense of yourself, especially during movement.
The main fibers found in fascia include collagen and elastin, and these fibers provide the mechanical properties of fascia, including transferring forces generated by muscle cells as well as yielding to various forces while maintaining the overall structure of fascia. Collagen, which is the most abundant protein in the body, is made up of three long protein chains organized in a triple helix. The shape of collagen gives fascia tremendous tensile strength (i.e. meaning it can bend or stretch without breaking). Elastin, also a protein, is thinner than collagen, and much more stretchy. In fact, elastin can stretch up to 230% of its original length and still return to its original shape. Elastin and collagen lie across one another and/or spiral around each other, forming a 3-D, interlacing structure that gives strength AND elasticity to the entire fascial tissue matrix (see image below).
The ground substance is the fluid component of fascia, and it fills the spaces between the fibers, cells, and nerve endings in fascia. Ground substance is a viscous, gelatinous, fluid material, primarily made up of water, glycosaminoglycans (GAGs), and hyaluronon (HA). GAGs can absorb water and help to provide plasticity to fascial tissues. HA lubricates collagen and elastin, and it acts like a hydraulic fluid that keeps muscles and joints gliding and sliding, rather than getting stuck.
What Does Fascia Do?
For many many years, anatomists would typically discard fascia as unimportant during cadaver dissections, thinking it was a non-functional tissue. However, in the past several years, that idea has been strongly disproved. Fascia is not only a tissue, it is also a system - an extremely important system to the functioning of our bodies.
Connection and Support. As discussed earlier in this post, fascia is responsible for connecting all bodily tissues to each other. Fascia also provides a soft-tissue framework of support for the entire body.
Force Transmission. Your fascial system mediates force transmission and enables movement in the human body. Forces from muscle contraction are transferred via fascial tissue (i.e. tendons) to bones, allowing your bones to create movement.
Proprioception. Proprioception is the ability to sense the position, location, orientation, and movement of the entire body or any of its parts, and it is governed by an array of sensory receptors found within fascia and muscle. Fascia actually contains 10x more proprioceptors than muscle tissue, and these highly sensitive proprioceptors respond to non-neural stimuli, like stretching, pressure, tension, compression, and shear forces. This initiates a network of reflexes between fascia and the nervous system, modulating and adjusting how muscles move. Thus, your fascia is SUPER important for your overall sense of your own body's movement.
Glide. Glide is a mechanical movement property of fascia that enables tissue layers to smoothly and safely move over each other. Healthy gliding of tissues allows the human movement system to function optimally. Proprioception is facilitated in part by optimal gliding movement of the entire fascial system. Also, force distribution from muscle to fascia to bone can only occur in the presence of optimal tissue glide. If there is decreased fascial glide (e.g. from dehydration, scar tissue, stiffness, etc.), it can lead to movement errors, discomfort, or even pain. For example, there is often reduced glide in the low back fascia of people with low back pain.
Association Between Movement and Fascia?
Your fascial system responds to the movement, or lack thereof, that you place upon it. Like much of the tissue in your body (e.g. bone, muscle, nervous, etc.), fascia responds to the stresses you put on your body to build either density or laxity. Fibroblasts synthesize and remodel collagen depending on the tension between the cell and ground substance. When the tension outside the cell is low (e.g. from lack of movement, sedentary lifestyle, etc.), there is not much collagen production. When under high tension (e.g. during exercise or daily movement), the fibroblast will increase collagen production. Thus, lack of regular movement, or total immobility, will give the fibroblast little-to-no appropriate stimulation, which will have a negative impact on the formation of a healthy collagen matrix. Thus, the health of your fascial system largely depends on your daily movement "diet."
Additionally, any disturbance to the architecture of the fascial system (e.g. from injury, surgery, disease, aging, over- or under-training, poor hydration/nutrition, anabolic steroids, etc.) can negatively affect functional, healthy movement. When fascia lacks optimal flexibility, the nervous system is also affected, leading to reductions in overall proprioception and motor control. Thus, issues with the structure of the fascial system can negatively impact movement quality and control. This can put a person at risk for injury or pain.
Your fascia is essentially your soft-tissue skeleton. It wraps around, interpenetrates, and connects every organ and tissue in your body. Fascia is quite literally everywhere in the body. Fibroblasts, specialized sensory receptors (e.g. proprioceptors), collagen, elastin, and ground substance are the components that make up your fascial tissue. Fascia is responsible for mediating force transmission to enable movement in the body, and your fascial tissues also house a significant number of proprioceptors, helping to ensure that movement is as efficient and coordinated as possible. Your fascial tissues respond to the stimulation your place upon it, whether it be from regular physical activity, or a lack thereof. When your fascia is healthy, the entire human movement system operates way more efficiently and safely. When your fascia is not very healthy (e.g. from scar tissue, lack of movement, dehydration, etc.), your overall movement quality suffers, putting you at risk for pain and/or injury.
As always, the information presented in this blog post is derived from my own study of human movement, anatomy, and yoga. If you have specific questions about your fascial system, please consult with your physician, personal trainer, and/or private yoga teacher. If you are interested in private yoga and/or personal training sessions with me, Jackie, email me at firstname.lastname@example.org for more information about my services. Also, please subscribe to my website so you can receive my monthly newsletters (scroll to the bottom of the page where you can submit your email address). This will help keep you "in-the-know" about my latest blog releases and other helpful yoga and wellness information. Thanks for reading!
~Namaste, Jackie Allen, M.S., M.Ed., CCC-SLP, RYT-200, RCYT, NASM-CPT, NASM-CES, NASM-CNC
Lesondak, D. (2017). Fascia: What it is and why it matters. Handspring Publishing.
Miller, J. (2014). The Roll Model: A step-by-step guide to erase pain, improve mobility, and live better in your body. Victory Belt Publishing, Inc.