Fascia Facts

(This page is a combination of the first three blogs posts on fascia)

What is Fascia?

Fascia.  An up and coming buzzword that’s attracting a lot of attention.  When explaining fascia to people I describe it as that white filmy stuff that wraps around meat (muscle).  In some places it’s thin and wispy, while elsewhere very tough and thick.

Deer tenderloin with fascial layers
Here my husband, Bill, is cleaning a deer tenderloin. He’s lifting up the superficial fascia, which is fragile and easy to separate. Underneath is the deep fascia which is much denser and firmly adhered to the muscle. The deep layer looks like one thick layer, but it is actually multiple layers of criss-crossing collagen fiber bundles. If you look at it closely you may be able to identify these crossing fibers.

Fascia can be easily lifted from the muscle in some parts of the anatomy, yet in other places it’s so firmly attached that separating it requires cutting into the muscle fibers (the parts of the steak you throw to the dog).  These differences – called regional specialization – are based on location in the body and reflect the different roles the fascia fulfills according to the demand placed on it.  For example, the iliotibial band (ITB or IT band) running down the outer part of the thigh is one of the thickest, toughest pieces of fascia in the body.  The high forces transmitted throughout the lower limb require such a design.  By contrast, the fascia of the inner part of the arm or forearm is not nearly as thick as the ITB since it does not handle the same amount of load.  

The literature on fascia has been very confusing over the years, which has not helped our understanding of this connective tissue.  As often happens, people like to name things after themselves and fascial anatomy is no different.  This has led to multiple different names for fascia throughout areas like, for example, the abdomen and pelvis.  Not only is this confusing, but it also gives the false impression that these differently named regions of fascia are separate structures, when they are actually one seamless network.  From head to toe, right to left, front to back, the fascia is continuous, intermingling, and creates relationships throughout the body:  between the shoulder and the shin, the hand and the head, even the back and the bladder.      

When looked at with the naked eye or even under a microscope fascia can look very disorganized and messy, like the deep fascia on the deer tenderloin in above. This is why some sources categorize deep fascia as irregular dense connective tissue.  But when separated by layer, it is actually found to be quite orderly with collagen fiber bundles laid down in a very organized manner, parallel to each other within that layer like fingers on a hand.

Fingers depicting collagen fiber bundles lying parallel within layer
Hands depicting space between fascial layers
Appreciating the layered formation of the fascia is key to understanding how this tissue functions, what can go wrong, and how to fix it. The collagen fiber bundles in each layer lie parallel to each other, much like my fingers. But in the next layer those collagen fibers are oriented in a different direction. They are thought to govern movement according to the orientation of the fibers in each layer, and require separation (space) and lubrication (slide) between the layers.
Macroscopic and microscopic images of layered formation of fascia.
This is a wonderful depiction and explanation of the layered formation of the deep fascia, taken from the article “Fascia: The Forgotten Structure.” Used with permission from Carla Stecco, MD.

Fascia is made of many cells (essential for the life of the tissue), fibers (primarily collagen and elastin or elastic which provide structure and support), and a ground substance uniting it all (water, ions, and glycosaminoglycans or GAGS which make it adaptable).

Depiction of layers from skin to muscle
I call this the lasagna slice, complete with hair. Basically you can follow the layers from skin down to muscle. It’s not apparent in this drawing but the thinner white layer closer to the skin (labeled the superficial fascia) is really two layers. The thick, white layer of deep fascia on top of the muscle is actually 2-3 layers of fascia. These are separated by loose connective tissue full of hyaluronan, here labeled as the hyaluronic acid layer. It’s really not such a neat, isolated layer as depicted in yellow here, but more densely scattered between each of the deep fascia layers. When properly functioning it serves to provide space and slide between these layers. (Original source unknown.)

The layered formation of the fascia has only recently been demonstrated by researchers.  The superficial fascia has two tissue layers, while the deep fascia has two to three layers according to body region.

Picture of real time ultrasound showing tissue layers of thigh
Ultrasound image of the tissue layers of the thigh. Here the space between the layers is much more visible than in Figure 3. Normal functioning of structures (muscles, nerves, blood vessels, organs, etc.) relies on the integrity of this spacing in the nearby fascial layers, as well as the associated slide between the layers. Courtesy of Antonio Stecco, MD, PhD.

  They are separated by layers of loose connective tissue (LCT), which has a very high content of elastic, water, and a substance known as hyaluronan (also called hyaluronic acid or HA).   This is our body’s biochemical lubricant that provides space and slide between tissue layers. HA is found in connective tissues throughout the body, and also happens to be an ingredient used in injections to help joints move better, like the knee.  The integrity of this sliding system is thought to be key to pain free movement of joints and overall function. 

Fascia is loaded with nerves, which is another feature we have only recently come to appreciate.

Microscopic innervation of deep fascia
Dissection, staining, and magnification of the deep fascia demonstrate the presence of many nerve endings that perceive temperature, pressure, movement, and noxious stimuli that can potentially produce pain. The body would not harbor these structures in the fascia unless they served a purpose, namely for perceiving information about the status of the body. Used with permission from Carla Stecco, MD.

  Chemical staining of the fascia and viewing slices under a microscope reveal the presence of a variety of nerves that perceive pressure, stretch, temperature, and pain.  This is remarkable to comprehend, as fascia has historically been considered a tissue existing primarily for containment purposes – not a potential source of pain!  Once again, the demand dictates the structure: body regions that need more information in order to keep us safe and functioning (wrist, ankle) have a higher content of nerves in the fascia as compared to areas like the elbow and knee, which are better suited for stabilization.  In the muscles, fascia is connected to the portion of the nerve that turns it on (muscle spindle).  Conversely, near the tendons the fascia communicates with the mechanism that turns it off (golgi tendon organ or GTO).  Fascia surrounds the nerves to protect, cushion, and facilitate glide for pain free mobility and function.

Fascial layers provide protection to nerves
The fascia and loose connective tissue between the fascial layers serve to cushion and protect a nerve as it passes through an area, while also facilitating pain free movement of the nerve. In this publication the research team at the University of Padova, Italy, demonstrated such a relationship between the musculocutaneous nerve of the arm and the surrounding connective tissue. Used with permission from Carla Stecco, MD.

Nerves also have to pass through the layers of fascia to reach their target structure:  skin, muscles, blood vessels, sweat and oil glands just to name a few of the structures the nerves communicate with.

Points of potential entrapment as nerves travel to surface of skin
Schematic of multiple potential sites of nerve entrapment along the route to a target tissue. We often focus on the larger nerves such as the sciatic in the leg or the median in the carpal tunnel. But it’s good to appreciate that countless small nerves traverse through these layers, making their way to the surface to give us the sensations of cold/heat, pressure, movement, and pain. Taken from the article “Fascial Entrapment Neuropathy,” and used with permission from Dr. Antonio Stecco, MD, PhD.

Internal organs like our stomach, bladder, ovaries, prostate, and intestines are lined with fascia full of nerves which coordinate the involuntary, autonomic functions these organs fulfill.  

Depiction of fascia, nerves, and stomach
The relationship of the fascia, autonomic nervous system, and internal organs is extremely complex. Here the stomach is depicted with its associated fascia that penetrates into the walls lining the stomach. The nerves embedded in this fascia orchestrate the precise timing of the movement of food to different parts of the stomach as it is processed. The integrity of this timing depends on the associated fascia functioning normally. Used with permission from Antonio Stecco, MD, PhD.

Where is Fascia Found?

The easy answer is everywhere!  No, it’s not to the ends of your hair but your hair follicles are embedded in tissue layers that exchange nutrients which must pass through the fascia.  Your fingernails and toenails, embedded in a soft tissue matrix, also rely on the health of the underlying fascia to allow nutrients in and waste products out.  The same holds true for your teeth and the gums – the fascia plays into oral health.  Most conversations about fascia associate it with muscles, which indeed have a very intimate relationship with the fascia.  Certainly big, powerful muscles like the latissimus dorsi (lat) or hamstrings (hams) relate to the fascia, but so do the tiny muscles that rule eye movements.  Joints also have specialized fascia surrounding them (often called retinacula) to provide stability, which is why the fascia in these areas is thicker and less flexible. This fascia at the joints is often inseparable from and continuous with the joint ligaments, even though most anatomy texts illustrate them as isolated bands. 

Fascia surrounds all the organs in the body, holding them in place so they don’t get tossed around when we turn a cartwheel or roll over in bed.  Not only does fascia encase each organ, but it also penetrates into the organs with nerves that orchestrate organ function.  Fascia lines our tendons, aiding glide with every muscle contraction.  Similarly, fascia can be found surrounding nerves to cushion, protect, and promote glide with every movement.   In a nutshell, fascia communicates with every muscle, nerve, vessel (artery, vein, lymphatic), organ (intestines, stomach, bladder, ovaries, prostate, lungs, etc.) in the body.  It’s one of the only structures that somehow touches every other anatomical structure and bodily function. 

Because it’s so pervasive, I like to point out that fascia is no respecter of the specialties we create in healthcare:  gastroenterology, obstetrics, gynecology, orthopedics, dermatology, nephrology, ophthalmology, endocrinology, neurology, and whatever else I might have missed.  Similarly we have specialties in physical therapy that also artificially compartmentalize the body:  orthopedics, women’s / men’s pelvic health, vestibular, temporomandibular, neurology, geriatrics, foot/ankle, hand, integumentary (skin), pediatrics, etc.  It’s not to say these specialties don’t have a role to play in treating disease and dysfunction:  they do, and there are cases that merit the focused training these specialists offer.  But caution is warranted so we don’t get too myopic in our perspective and lose sight of the relationships between body regions and structures.  Fascia crosses over all these specialties impacting each and every aspect of the anatomy.  So when a body has multiple problems in multiple areas prompting consults with multiple specialists, it’s worthwhile to consider that the fascia might be the common element especially when problems persist, recur (heal but then return), or do not respond to appropriate care.    

What Does Fascia Do?

Way back when I was in physical therapy school I remember learning little to nothing about fascia.  I didn’t say they didn’t teach it, I’m just saying I don’t recall learning much about it.  In gross anatomy lab where we dissected cadavers all I remember about fascia is that it was in the way of the “important stuff” we had to learn about, like muscles, joints, tendons, nerves, bursa, etc.  Our goal was not to understand fascia, it was to get it out of the way.  Too bad, we missed a lot.  Fascia is also very different in an embalmed (preserved) cadaver as opposed to an un-embalmed or even a live subject.  The embalming chemicals as well as exposure to air completely change the properties and behavior of the tissue.  So what the majority of us in healthcare see of the fascia during our training is not very realistic in terms of connective tissue, especially fascia.  No wonder so many of us emerge from school with practically no appreciation or understanding of fascia or connective tissue. 

Saint Louis University Physical Therapy Class of 1984
Saint Louis University School of Physical Therapy, Class of 1984. Seems so long ago and far away. It was! I’m there with my boofy hair, kneeling in the second row from the bottom, furthest to the left. Too funny! Hello to all my classmates!

For years many have mistakenly relegated fascia to be like Tupperware® containers for compartmentalizing and organizing structures throughout the body.  It’s true that fascia helps to maintain the form of the body providing order and support for muscles, tendons, nerves, blood vessels, and organs.  But if this was all it did, there would be no need for it to be so richly innervated.  There would also be no need for the layered formation – one layer would hold things in place just fine, like a twisty tie, rubber band, or duct tape. 

Many great minds have contributed to the growing body of literature which upholds the fascia as a key player in governing movement.  I like the word govern used in this sense because it implies allow, guide, restrict, but also prevent or impede.  When considering the musculoskeletal system (neck, low back, hip, shoulder, etc.), multiple theories exist as to how movement occurs.  Classical models have typically upheld that the brain stimulates a muscle contraction which pulls on a bone causing movement at a joint.  Yet there are multiple problems with this model: 

  • Movement may involve only part of one muscle and part of another, according to the direction of movement;
  • Movement is not robotic with only one joint moving at a time, but a complex series of activities that involve many joints and multiple muscles turning on and off in a very complicated and coordinated pattern as needed;
  • Muscles and tendons often don’t fully attach to bones – they also connect to fascia; 
  • Coordination of movement has to be very adaptable and dynamic, capable of modifying in a split second according to the demand on the body.  While the brain is amazing, it can’t possibly orchestrate every single element of all movements we make in multiple body regions 24/7.  There has to be a peripheral mechanism assisting in this.  The fascia, by virtue of its close relationship with the nervous system as well as its pervasive nature throughout the body, is perfectly positioned to play a key role in governing movement.    

We give joints far too much focus in health care.  Maybe that’s because they are easy to see on imaging (X-ray, MRI) and erroneously assumed to be the source of most pain.  But joints don’t just move themselves, they are moved by connective tissue.  We also give muscles too much credit for ruling musculoskeletal movement; muscles follow orders, and only turn on and off in response to orders and ability.  While the brain certainly stimulates a voluntary muscle contraction, it can’t execute all aspects of the movement from initiation to completion and assure it happens in a smooth, coordinated manner. There is mounting evidence for the perspective that the fascia is the peripheral mechanism assisting the brain in accomplishing movement.  It makes sense if you recall that the fascia surrounds every nerve, joint, muscle, and tendon, and also has multiple routes of communication with the nervous system.   

But movement applies to more than just our neuro-musculo-skeletal system.  It is also crucial to bodily functions such as digestion, urination, reproduction, circulation, and respiration.  Disruption of movement in any of these entities interferes with function and ultimately the health of the organism.  I like to compare movement to a symphony or a choreographed dance:  timing is everything.  Each performer has a part to be executed at a precise time in a specific manner.  When one performer is off, it can disrupt the whole show.  Take, for example, digestion.  It can be said to begin in the head with the sight, smell, or even thought of food.  Chewing stimulates the stomach to begin preparation for digesting food.  We swallow and food moves smoothly and easily (or it’s supposed to) down our esophagus into our stomach, where it then moves into different parts of the stomach as the food breaks down.  Next in the performance is the role of the intestines as food moves along this pathway, stimulated by precisely timed involuntary contractions called peristalsis.  While the brain certainly has a part in all this, the fact that peristalsis continues even after the severance of the brain from the spinal cord testifies to the presence of a peripheral mechanism playing into this activity.  The fascia, lining the organs and richly supplied with nerves capable of stimulating peristalsis along its path, is ideally suited to coordinate this activity.  Disruption of any player in the show may lead to dysfunctions like constipation, diarrhea, ulcers, flatus (gas), food intolerances, reflux/GERD, and irritable bowel syndrome (IBS).  Running tests on the organs for many of these conditions (like colonoscopy or endoscopy) typically does not reveal the source of the problem.  This is because the problem frequently isn’t the organ itself – the problem is the dysfunctional fascial environment in which the organ is trying to exist and function.         

What Can Go Wrong with Fascia?

Movement is life, and this applies to the fascia especially when considering the layers of the deep fascia.  It is essential that separation and lubrication (space and slide) be maintained between these layers if they are going to function properly to govern movement of the neuro-musculo-skeletal system as well as multiple involuntary organ functions.

Fascial layers sliding versus densified.
Depiction of the deep fascia layers. In A, the layers are spaced apart and free to slide on each other. In B, a fascial densification is shown where the tissue slide and space are compromised. This disrupts movement between layers which can exert a negative impact on the surrounding structures, such as joints or organs. Used with permission from Antonio Stecco. MD, PhD.

Studies of anatomy have shown that the loose connective tissue (LCT) found between the fascial layers plays a critical role in maintaining this space and slide.  A key component of the LCT is the biochemical hyaluronan (HA).  Produced naturally in our body and found throughout our connective tissues, HA is a very interesting substance that has, in a way, multiple personalities.  When it’s happy and normally functioning, HA binds with water which keeps the LCT from getting too thick.  This promotes the critical space and slide between the tissue layers.  But when HA is unhappy or stressed, it becomes tangled on itself like my hair after washing it.  It also changes to its other personality (HA, not my hair) and becomes water repelling.  This makes the LCT thicker (like soup that needs more broth), and HA becomes space occupying instead of space creating.  This in turn causes the layers to adhere instead of slide, disrupting movement of bones and bowels depending on where the problem is located.    

The next burning question is “Why does this happen?”  (Or what makes HA unhappy?)  The word that is thought to explain it best is overload. 

Donkey lifted in air by heavy cart
The poor donkey is obviously overloaded! An obvious illustration of overload, much like we encounter all day long in the form of trauma/injury, repetitive movements, and immobilization. Source unknown.

Overload comes in many forms, but basically boils down to three categories: 

  1. Trauma or injury
  2. Repetitive movement
  3. Immobilization

Let’s take a deeper look at these, because the only way to stay healthy and functioning is to understand what went wrong in the first place.    

Trauma and Injury.  Some cases are obvious, such as a motor vehicle accident, fall on the ice, or collision on the volleyball or basketball court.  Bones can be broken, ligaments torn, and tendons rupture.  These typically get lots of attention and are managed accordingly.  But in the absence of these glaring injuries it’s easy to believe you’re lucky and escaped harm.  Wrong.  Even when things aren’t torn or broken, the connective tissue is still traumatized and altered, resulting in a loss of space and slide in the deep fascia layers.  You guessed it:  the HA is unhappy.  Things heal and soreness improves.  Sometimes the tissue layers are restored to their prior state – namely with space and slide.  But sometimes they are not.  Keep in mind that in the event of bone, ligament, and tendon damage and healing there may still be a loss of slide in the tissue layers which can persist indefinitely – that can mean years.  Surgery is also a trauma as it alters the anatomy and changes how tissues move. 

Some traumas are easy to recall – we wish we could forget them.  Others were so long ago – maybe an ankle sprain in high school track – we don’t even think about them anymore.  It was bad at the time but seemed to heal and is no longer symptomatic.  That doesn’t mean full mobility and function are restored to the tissues.  I like to point out that pregnancy, labor, and delivery are traumas – to the mom and the baby, certainly in varying degrees.  While some women seem to rebound better than others, it’s good to appreciate that things aren’t always what they seem.  Preexisting issues in a woman’s body can predispose her to more struggles.  Talking about the babies, I strongly believe we grossly underestimate the traumas of childhood, possibly beginning at birth with a troubled labor and delivery. As they grow children are repeatedly subject to trauma.  I’m not trying to dramatize every bump or bruise.  But we start falling down from the moment we begin standing up.  Kids fall off their bikes or the swing, cry a bit, then eventually run back out to play while we marvel at their resilience.  I have to wonder if each of those episodes compromises a little bit of tissue slide, accumulates and over time, and eventually becomes the aches and pains of adulthood.  This is my platform for early intervention and not minimizing the complaints of children. 

Repetitive Movement.  All day long, every day, we do the same movements over and over and over.  Open a door, hold a phone, pull a lever, type on a keyboard, carry a toddler (often on the same hip), pitch a ball, etc.  Certainly our dominant side does more work for us and is subject to more use.  This impacts the rest of the body as it postures to support and perform the activity.  The same movement/activity repeated day after day has a tendency to bias the body and work some areas harder than others.  Studies show that even with 30 minutes of computer work or piano playing, we begin to accumulate biochemicals in the upper trapezius muscles and fascia (between the neck and shoulders) that can trigger tightness, pain, and dysfunction.  No wonder so many people are so tight and sore here!  Within reason the body can manage this.  But we are not machines that can keep repeatedly doing an activity.  Even a machine is subject to breakdown, and needs maintenance to overcome wear and tear.  Think about the tires on your car – rotating them is a good practice for avoiding uneven wear arising from the surfaces we drive on, the way we drive, the different demands on the tire according to where it is on the car, and the alignment of the car. Our bodies are subject to similar stresses, but rotating body parts is not quite as simple as tires.  Changing the activity as much and often as possible is a strategy, but may only be feasible to a point. 

Immobilization.  Research shows that when tissues remain in a position too long they are subject to physiologic processes that change their nature.  There is an accumulation of biochemicals including HA, which leads to crowding (loss of space) and binding (loss of slide) between layers.  Perhaps this accounts for at least part of the morning stiffness attributed to conditions like arthritis and plantar fasciitis.  As with trauma, some forms of immobilization are obvious:  a cast, splint, or bed rest.  Often immobilization follows a trauma, which is a double whammy compromising function of the connective tissues.  Time and immobilization typically heal traumatized tissues and diminish pain (hopefully).  But complete healing requires restoration of the tissue layer space and slide.  

Similarly, sitting – especially for extended periods of time – promotes this accumulation and binding of HA in the tissues.  No, I am not saying that “sitting is the new smoking.”  That’s a bit dramatic (see my video on this subject). But it does harbor issues and is a form of immobilization.  Symptoms may not be apparent while sitting, but with coming to standing, pain and stiffness in the low back, hips, knees, and perhaps feet may be pronounced for at least the first few steps.  Once the tissues are lengthened and shortened a few times with walking then they are primed to move a little better.  Fascial layers with healthy space and slide can accommodate the lack of movement associated with sitting, and meet the demand to rise and walk without difficulty.  But tissues that are already harboring dysfunction will exhibit more difficulty accomplishing this seemingly simple task.  We typically attribute this to old age and arthritis, but seeing this improve quickly with restoration of tissue slide belies the arthritis explanation.    

What can be done to fix it? 

LOTS!  It’s far from all bad news!  The characteristic of the tissue that gets it into trouble (modification in response to overload or stress) is the same quality that can be accessed to reverse it from dysfunction back to function.  So not all stress and overload are bad; they just have to be applied in an appropriate dose and location.  I am a big believer in the manual therapies especially those, as you might imagine, that target the connective tissues like fascia.  There is a smorgasbord of different soft tissue techniques as well as certifications out there, and I won’t even try to name them all.  Some clinicians pull a bit from each for their treatment plate, and some fill their plate with one particular approach – usually whichever one they have found to work the best and they feel most proficient using.  Many techniques have studies that show they are beneficial. The truth is for many manual therapy interventions, including joint mobilization/manipulation, and even dry needling, the exact mechanism of change is not precisely understood.  But that doesn’t mean we shouldn’t utilize them in the meantime.  Whatever helps people reduce pain, return to moving and functioning, minimize/eliminate medications, and avoid surgery is worthwhile to utilize.   

Since graduating PT school in 1984 I have pursued and enjoyed attending many courses from many different perspectives (Fascial Manipulation-Stecco®, John Barne’s Myofascial Release, Stanley Paris, Myopain Seminars, Institute of Physical Art, MSU College of Osteopathic Medicine, Postural Restoration Institute®, and many more) always looking for better ways to address problems and help patients (myself included). While many of these have added to my current knowledge base and practice approach, the one that I have found to work the most consistently and impressively for me has been the Fascial Manipulation-Stecco® method (FM).  The motto of the Fascial Manipulation Association, “A Knowledgeable Hand is Potent,” is so true.

The Fascial Manipulation-Stecco® logo. The motto is in Latin so as to be universal, and is translated “A Knowledgeable Hand is Potent.”

  Knowledgeable hands do not necessarily go with lots of letters after one’s name, nor do knowledgeable hands always accompany a particular health care field or license.  To my way of thinking, knowledgeable hands are developed by a person who: 

  • Uses their hands regularly and frequently for palpation in assessment and treatment
  • Is open-minded and seeking, even when it means they need to revise their paradigm, which is very demanding
  • Embraces a life-long path of learning
  • Is willing to give all they can to each patient, and is also passionate about helping people recover and thrive

So I celebrate anyone who does all this, regardless of their professional silo or which approach(es) they utilize.  Having said that, this is my blog so I’m going to focus on the interventions I have found to work best in practice!  These will be addressed on separate pages. 

Resources:

  • Stecco A.  Fascial entrapment neuropathy.  Clinical Anatomy 32:883–890 (2019).
  • Stecco C.  Function atlas of the human fascial system.  Churchill Livingstone Elsevier, 2015. 
  • Stecco C, et al.  The fascia:  the forgotten structure.  IJAE, Vol . 116, n. 3: 127-138, 2011.
  • Stecco L. 
  • Macchi V, et al.  Musculocutaneous Nerve: Histotopographic Study and Clinical Implications.  Clinical Anatomy 20:400–406, 2007. 
  • Pavan P, et al.  Painful connections: densification versus fibrosis of fascia.  Curr Pain Headache Rep (2014) 18:441
  • 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, Volume 2, Number 4, December 2009. 

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