new study discusses the relationship between fascia, pain and dermatomes, myotomes & fasciatomes

FASCIA AND ITS RELATIONSHIP TO CHRONIC PAIN AND THE FASCIATOME

Last week the STECCOS, along with six other Italian researchers, published a study in Clinical Anatomy titled  Dermatome and Fasciatome.  Although I’ve covered dermatomes, myotomes, scleratomes, etc (HERE), etc, I’ve never even heard of the analogous formation found in FASCIA — the fasciatome (although on the surface it sounds like it could be related to Tom Meyer’s ANATOMY TRAINS).   Let’s dig into this study and see if we can figure out what’s taking place and why fasciatomes might be important to understand clinically.

The authors started by tearing down a sacred cow; the dermatome.  After revealing discrepancies between various dermatome charts, we learned there is a re-evaluation taking place, based on referral patterns from DEEP FASCIA.  We were then hit with this; “The dermatome is important for esteroception, whereas the fasciatome is important for proprioception.”   OK; I’ve shown you that fascia is heavily related to proprioception (HERE), we’ve discussed NOCICEPTION numerous times, and I’ve even dealt with INTEROCEPTION.  But what the heck is “esteroception“? 

Several sources, including a 2012 lecture by Dr. Antonio Stecco given at Italy’s University of Padova (Anatomy of the Fascial System) provided a clue, when he spoke of “The separation between esteroception (skin) and proprioception (deep fascia)“.  Esteroception is simply different spelling of the word Exteroception.  Allow me to explain. 

Proprioception is the sensory input that comes from very specific receptors whose job is to feed information back to the spinal cord and brain concerning things like movement, stretch, and position of joints, connective tissues, muscles and the body as a whole.  Interoception involves sensory inputs that are derived from within the body (nope, not emotions).  Examples could include HEADACHES, the feelings of hunger or thirst, CENTRAL SENSITIZATION (brain-based pain), etc, etc, etc.  Likewise, exteroception involves sensory inputs into the body from things that are outside the body, mostly referencing functions of our special senses — tasting, touching, smelling, seeing and hearing.  Here are some cherry-picked sentences from the study’s abstract.

“The dermatome represents the portion of tissue composed of skin, hypodermis, and superficial fascia supplied by all the cutaneous branches of an individual spinal nerve; the fasciatome includes the portion of deep fascia supplied by the same nerve root and organized according to force lines to emphasize the main directions of movement. The dermatome is important for esteroception, whereas the fasciatome is important for proprioception. If they are altered, the dermatome shows clearly-localized pain and the fasciatome irradiating pain according to the organization of the fascial anatomy.”

While the dermatome and fasciatomes are certainly different, note that both involve fascia.  For instance, we already know that skin is heavily related to fascia (HERE) as are cutaneous nerves (which can themselves easily become “entrapped” or “entangled” in adhesed fascia — HERE).  Alter the function of fascia (CAN ANYONE SAY ‘FASCIAL ADHESION’?) and sooner or later you will have problems.  Stecco’s study is all about trying to improve this information to more accurately figure out where people’s pain and dysfunction might be coming from and provide better solutions for addressing it (solutions that go far beyond standard fare such as THE BIG FIVE). 

While I was under the impression that the DERMATOME MAPS / CHARTS I learned back in the late 1980’s were rather cut and dried, it seems I would be wrong.   Dermatomes were discovered in 1886 and have undergone numerous revisions since, with plenty of debate taking place even now as to what they should look like.  In researching this debate I found a 2011 paper from the Journal of Orthopedics and Sports Physical Therapy titled Conflicting Dermatome Maps: Educational and Clinical Implications, which revealed the extent of the controversy. 

“The textbooks  commonly used in medical and allied health programs  contain multiple, conflicting dermatome maps. These maps place clinically important dermatomes in varying  locations.  Because the dermatome maps currently in use were developed in the late nineteenth and early twentieth centuries using a variety of techniques, we believe that the cutaneous distribution of spinal nerves to the limbs should be re-evaluated.“

After agreeing with this assertion by providing more proof from a 2018 study (Observations on the Inconsistency of Dermatome Maps and its Effect on Knowledge and Confidence in Clinical Students), Stecco’s team revealed why this debate is important to resolve.  “No study has distinguished the innervation of the skin from that of the deep fascia. However, we now know that the deep fascia is very well innervated and that it could be a source of pain radiation with different patterns from the skin.” 

Interestingly, this theory came about when a team of researchers published a study on the THORACOLUMBAR FASCIA (I’ve mentioned it several times, including HERE) which determined that sensory mapping of the skin is different than sensory mapping of the fascia underneath.  In other words, “the deep fascia can be innervated differently from the overlying skin and consequently have its own map of pain distribution.” 

The authors did a literature review, starting with almost 800 studies and paring it down to just under forty that met their criteria for “fascia innervation” (fascia’s nerve supply).  Using definitions of superficial fascia as “fascia connected to the skin,” and deep fascia as fascia “connected by fibrous septa (retinaculum cutis superficialis and profundus, respectively), which impart specific mechanical properties to the subcutis,” they set about making or breaking their hypothesis.  

Even though I’d heard it before, one of the findings that intrigued me most concerned their team’s determination that only about 70% of the power of contracting muscles pulls on bones, with the rest pulling on fascia.  In other words, one of the many reasons fascia is critical for understanding both BIOMECHANICS and MUSCULOSKELETAL PAIN is that it can actually act as a soft lever (HERE is one way this happens).  Citing a phenomenon I routinely see in clinical practice, the authors discussed how fascia in one place (say the CERVICAL FASCIA) can dramatically influence or affect fascia in a very distant area, say the thoracolumbar fascia or even the PLANTAR FASCIA. 

“Every time the muscles contract, they produce tension in the fascia and this mechanical input can create specific fibrous reinforcements day by day, visible macroscopically during dissection. Thanks to these myofascial connections, anatomical continuity is created among various muscles involved in the same directional movement, challenging the classical concept of muscles as morphologically independent actuators.”

In other words, the old model of anatomy — with muscles attaching to bones in order to pull on them — while not necessarily dead, is far from 100% accurate.  I think it was Tom Meyers who said something along the lines that we are not made up of 650 individual muscles, but instead, of one muscle found in 650 unique but interrelated pockets of fascia.  

As you might expect, this helps explain why muscular coordination is not jerky, but instead flows smoothly, gracefully and fluidly.  But even this understates what’s really being shown by this team of researchers.  Enter myofascial expansions.  The areas where the various connective tissues are connected to each other (fascia, PERIOSTEUM, TENDONS, LIGAMENTS, APONEUROSES, etc) are referred to as “myofascial expansions,” which allows for the six primary movements that occur within the fascia itself; “anteposition, retroposition, adduction, abduction, intrarotation and extrarotation“.

The authors went on to discuss the numerous sensory nerve fibers contained within various types of connective tissues, as well as some of the astounding numbers of ways they can be stimulated, including a variety of inflammatory, chemical, electrical or physical stimuli.  The bottom line is that looking at these studies gave the authors the evidence needed to advance the idea of the fasciatome as it’s own unique pattern of referred pain — something important to grasp because anyone who has seen patients for any length of time realizes how many “weird” patterns of radiating pain one can see.  BTW, the bottom sentence in the quote below describes something I routinely see in practice.

“The classification of somatic pain also combines pain related to the deep fascia with muscular pain (deep somatic pain), whereas the skin is related to superficial somatic pain. Consequently, the innervation patterns of the deep fascia probably follow myotomes rather than dermatomes. The anatomical organization of the deep fascia can also create a massive radiation of pain along the fascial reinforcements, which follow a different pattern from the skin.  According to this distinction, it is easy to explain the ‘anomalous’ pattern of pain radiation that does not follow a specific dermatome…..   The descriptor patterns of fascia and skin can lead to misinterpretation of fascia-related pain in the lower back pain as neuropathic.”

This helps explain why fascia has been shown to be a bigger culprit in chronic low back pain than muscle (HERE).  Before continuing, allow me to provide you an example of this phenomenon.  Last evening I treated a young (very young) man who had been struggling since high school (he is a recent grad) with the low back pain and sciatica; arguably the number one problem the average chiro sees on a day to day basis. 

After checking for, finding, and then breaking SEVERE FASCIAL ADHESIONS that ran from the bottom of his thoracolumbar into his buttock (SCN ENTRAPMENT), and then upward into his MID UPPER BACK, ALMOST TO HIS NECK, he could not reproduce his pain — a rather common feature of treatment in our clinic (HERE).  This was particularly significant for him considering he had been dealing with this problem for several years, seeing several specialists and having MRI’s (plural).

Back to the study.  Stecco and crew actually went a step further, showing that in many cases dermatome charts are rather unhelpful, listing several studies (Murphy et al in 09, Kurosawa et al in 2015, and Murakami et al in 2017) that described use of dermatomal patterns for diagnosis as, among other descriptors, “not useful“.  Why not?  Because nerve root pain has historically and frequently been shown to not follow ”established” dermatomal patterns. 

After giving several reasons for this, the authors gave a mind-blowing example that could easily be the source of lots of what I have referred to over the years as both PIRIFORMIS SYNDROME or entrapment of the superior clueal nerve (see earlier link).  In other words, there is the possibility that even though I would still treat these problems in an almost identical manner, both models are technically incorrect (SOMETHING WE DISCUSSED A FEW DAYS AGO).

“Most interestingly, pain referred to the buttocks, posterior thigh or posterior calf cannot be due to radicular compression, but to excessive tension of the deep fascia along a specific line of force. This tension can activate all the free nerve endings along that line, giving rise to pain that simulates, for example, ‘S1 radiculitis’.”

HOLY SCHNIKES folks; once you realize just how many people — most of them women — are suffering with chronic hip / buttock pain, you can start to grasp just how relevant Dr. Stecco’s study really is.  Oh; and besides SCIATICA (leg pain), we could actually say something almost identical about RADICULOPATHY — numbness, tingling, pain, etc, in the arm and hand, considering they gave examples of this as well (Slipman et al in 1998; Schirmer et al in 2011, Standring in 2016; Ladak et al in 2014; and Furman et al from earlier this year).   I’ll let the authors sum things up with these three sentences.

“Nerve root stimulation causes muscular contraction, allowing the bone to move, but it also stretches the overlying deep fascia thanks to myofascial expansions. As such expansions are located along the main spatial directions, we suggest that all the fascial receptors along that line are stimulated during a movement in one direction, and consequently all these inputs coming from one line converge on a specific root.  If altered, the dermatome gives clearly localized pain and the fasciatome irradiating pain, in accordance with the organization of the fascial anatomy.”

In other words, what I have been documenting clinically for the past two decades is being fleshed out, described, and proven for everyone to see and understand.  Once more we get a glimpse of why fascia is so important, helping explain why growing numbers of both treating and research physicians are referring to it as medicine’s Holy Grail —- the cause of sickness, disease and pain (HERE, HERE, HERE, HERE and HERE). 

What this means is that even if these experts are only partially correct, the implications for TREATING CHRONIC FASCIAL ADHESIONS as part of a COMPREHENSIVE PROTOCOL can be nothing short of amazing, much of it having to do with the fact that “chronically inflamed thoracolumbar fascia can undergo pathological changes leading to long-term worsening of symptoms” — something discussed at length HERE. 

Since this post could prove invaluable for at least a large portion of the tens of millions of American’s struggling with chronic musculoskeletal pain (or even in many cases, chronic illnesses, MYSTERY PAINS or MUPS), be sure to reach the people you love and value most by liking, sharing, or following on FACEBOOK.