In this day and age it seems like humanity has explored every nook and cranny of the Earth, let alone our own anatomy, so when it came out to the public just over a year ago that there had been a new discovery of an organ, it made headlines- well, in health science circles anyways!

It wasn’t long before that scientists were debating whether the mesentery, the folds of tissue providing support and circulation for our GI tract, was announced the 79th organ, now they may be claiming the 80th with the interstitium.

The interstitial tissues have been known about for well over a century. Known broadly as connective tissue, there are several types whose architecture varies with its functions. It may be noted here that bone, cartilage, and adipose are also connective tissue, often along with the blood and lymph, but not specifically included here. Here, we are talking about the connective tissue proper, sometimes referred to as fascia. Long since thought of as dense parallel stacks or a tangled mesh of fibres, as seen with dissected tissue on prepared slides for the microscope, the new medical technology such as the confocal laser microscopy and the digital video endoscope offers a new world to see which challenges us to re-think the way our bodies are structurally organized.

As Dr. Neil Theise, one of the researchers involved in the study put it:
“One can’t understand the mechanical properties of any tissue without understanding the lubricating and shock absorber potential of the interstitium…they are not dense connective tissue, they are distendable and compressible fluid- filled spaces”
( from an interview in

This fascial interstitium is not just a simple mesh of fibres but a complex, multi-layered system supported by a collagen network of slippery, viscous fluid- filled spaces that allow the gliding needed for the free movement of our bodies components. It is an interconnected web that fills in all spaces in our bodies. It provides shape, it distinguishes, at the same time connects cell to cell, organ to organ. Our internal world, with all its mechanical orchestra of pulsating blood vessels, squeezing bladders,
billowing lungs, rhythmic writhing of the digestive tract, not to mention our skin, muscle and bone, are cushioned and enveloped by this interstitium.

If scientific consensus allows, and it takes its place among all those other organized vital tissues, it would be considered the largest organ, overtaking the skin.

The interstitium allows communication between cells and the circulation in mechanical and chemical ways. It also drains into the lymph system. These properties may shed a light on the origins and behaviour of some diseases, and how some cancers metastasize throughout the body. Researchers may be able to extract the fluid from these extracellular matrix spaces of the interstitium for diagnostic purposes.

Further study of the interstitium may open up more appreciation of how complimentary medical treatments like acupuncture and fascial release therapy work, in part due to the conductive qualities of collagen when mechanically stressed, as with the turn of an acupuncture needle or the pressure and friction of a Fascial Manipulation treatment.

The connective tissue, for a long time visible to the naked eye of the anatomist, and explored ever more deeply and minutely with the compound and then electron microscope- but not yet fully appreciated as a wholly functioning entity in and of itself, until more recently with advances in technology that allow us to see it ‘in vivo’. Physicians and scientists are now able to see the interstitium as it really is inside the living body.

So pretty soon we’ll be able to understand more of what you already know about the positive effects of your massage or acupuncture session!