What are fasciae (or fascias)?

If they are very often mentioned by many manual therapists as being an integral part of their practice (there are even fasciatherapists), the anatomical situation of the fasciae, their role and thus their interest in the therapeutic process remains rather unknown by the majority of patients. There is sometimes even a mysterious, if not magical, side to the description that is given. However, these are very real tissues, whose properties and roles are indeed of fundamental importance in many consultations.

In a very general way, the term fascia designates the connective tissue, i.e. the tissue that links the different elements of the body together (muscles, tendons, bones, visceral organs, skin...). In English we speak of "connective tissue", a term that is more evocative of what fascias actually are. It is therefore very roughly the "filling" tissue of the "empty" spaces of the body.

From a functional point of view, there is not only one but a multitude of different fascias, some of which are quite well known, even if we often ignore that they are actually fascias. We can mention

• The peritoneum, which maintains and protects all the visceral organs (particularly involved in peritonitis, a classic complication of an untreated appendicitis attack),
• The meninges that protect our central nervous system (brain and spinal cord),
• The periosteum, which is the outermost layer of the bone
• The fascia which is the little translucent layer around the muscles. When you eat a steak sometimes, it is difficult to cut a small transparent membrane, it is a fascia.
• The pleura that surrounds the lungs
• The pericardium which is the small connective tissue sac that surrounds the heart.

Of a relatively similar composition at the beginning (they have the same embryological origin), the various fascias individualize and organize themselves differently with time and according to their anatomical situation and the constraints to which they are subjected. This makes them fundamental structures because of their quantitative importance and their mechanical properties.

The connective tissue (and therefore the fascias) represents two thirds of the total volume of the body, as well as a quarter of the water in our organism (i.e. about 20% of the body weight).
They are therefore mainly composed ofwater, a variable proportion of fatty tissue and cells called fibroblasts whose role (in a very basic way) is to maintain the shape of the tissue, to give it coherence. One could almost say that without fibroblasts we would be nothing but a puddle.

By putting in continuity all the anatomical elements that constitute us, the fascias constitute in a way the "glue" that maintains us, while being sufficiently elastic to allow us to face the daily life and its multiple constraints (falls, shocks, repetitive movements...). Moreover, because of their omnipresence in the organism, the fascias are also responsible for the transport and the protection of the vascular system and thus for the good "nutrition" of the whole body.

It has also been demonstrated that fascias are "hyper-reactive" to mechanical stimuli. In continuous movement (observable to the naked eye and described in particular by many surgeons), the fascias freeze completely when a contact is applied to them and the movement resumes as soon as the constraint is lifted.

"You can see the fascia on the surface of the muscles moving. You can see this movement. It is the fascia that moves, not the muscle [...] As long as we are in the dissection, nothing happens, you put everything down, you wait 5 to 10 minutes, you see the movement appear. The fact of traumatizing it must freeze things. You have to wait a while for the movement to reappear, I don't know what it's due to."

Dr. Jean-Marc Claise, hand surgeon

Here is a video by Dr. Guimberteau entitled "Promenade sous la peau" which highlights the fasciae on living tissue:

It is this characteristic and this capacity of the fascial tissue to "respond" to a mechanical stimulation that makes it a fundamental tool for your osteopath. On the one hand because thanks to these capacities the fascias can keep in memory an important trauma, even a very old one. It is in the alteration of the fascial movement that the practitioner can perceive an anomaly just by placing his hands (with a very light contact since it is not a question of "silencing" the fascia in question). On the other hand, once this anomaly has been identified, it is very often by re-establishing a balanced movement of the fascia that the therapeutic effect is produced.

The effect may be immediate in the case of work on muscle fascia, for example, or it may be felt at a greater distance from the consultation when the work is done further upstream from the painful area. Some studies have even shown that the state of compression or stretching of a tissue can change its function by influencing the expression of the genes of the cells making up this tissue. Thus, an organ or a muscle whose fascia is compressed or stretched will not be able to function efficiently. This is why the fascia are essential in the understanding and treatment of a painful symptom, all of which can be explained very well.

Finally, the way in which the architecture of a tissue influences its functioning is found in what is called epigenetics, which highlights that not only the state of compression or stretching of a cell influences its gene expression (and thus its function) but also that environmental factors (fatigue, stress, diet, lack of sleep...) could have the same effect. It's exciting, but that's another story...

Damien Fabre
Osteopath in Versailles
78 - Yvelines