What is the Interstitium REALLY all about?

Michelle Dickey for Yoga Medicine® on what the interstitium is, what it does, how it can affect your yoga practice, and how to keep it healthy.

The Interstitium: Breaking Down the Mystery

What is all this talk about our “new human organ”? Did scientists really NOT know about an entire organ in the body? You might have heard that a new human organ has been discovered. On March 28, 2018, scientists named the new organ the “Interstitium”. Upon first reading this, my instant reaction was to wonder how scientists could possibly discover a new organ. We’re all aware of our heart, lungs, stomach, kidneys, etc. being organs, so how is it that one got overlooked?

In 2017, I was lucky enough to take part in Yoga Medicine’s cadaver lab where we dissected untreated cadavers. Untreated means that the body is not preserved with formaldehyde nor had the body been previously deconstructed. Throughout this dissection, Master Dissector Todd Garcia would name the various tissues that we were handling and moving through. This included all the organs. Not once in this dissection, did the trainer stop and hold up anything and say “this is a thing without a name,” and then move on. So, it baffled me when I saw the headline about discovering a new organ. Especially because my hands had been in a cadaver, learning about all the different components within the human body.

What is it?

The newly discovered interstitium is defined as “a contiguous fluid-filled space existing between the skin and the body organs, including muscles and the circulatory system.” [1] That means that this organ covers the whole body from head to toe and is underneath our skin but before our body organs. Our skin isn’t that thick; it’s about the thickness of a few pieces of paper. Somehow this new organ lies under that single piece of paper before the muscles? That seems pretty crazy.

Now it becomes a little easier to see why this organ was hiding from us for so long. With the more common organs such as the heart and lungs, etc, we have a large mass of body tissue that is palpable. These more common organs are able to be seen right away within the body as they have their own individual texture and feel to them that differentiates them from the other body tissue surrounding them.

Where is it?

But this interstitium, it’s the king of hide-and-seek. In a cadaver, peel off the skin, first layer of adipose, and fascia, and you’re left looking at, what appears to be, the beginning of the silvery layer of deep fascia that covers the muscles. At least that’s what was previously thought.

In the video link below [2], you can watch as Fascial Researcher Gil Hedley dissects various parts of the body and finds in each area that between the skin and the muscles and organs of the body, there is this layer that is extremely difficult to see unless you know to look for it. Watch as Gil Hedley expertly dissects through this “fuzzy layer” or “perifascia” and shows that this isn’t just a slimy goop of boogers hanging out on top of things, but it’s a very fine layer of collagen and elastin that has rebound properties and tensity.

Watch the video Interstitium aka: Perifascia

This tiny, tiny layer of fuzz, is so thin it’s transparent. This is the “new” organ that is finally coming out into the open. The layer is tricky though because when exposed to the elements, it hardens and turns brown and doesn’t seem to be of any true importance. This hardened layer was thought to be a densely-packed stack of connective tissue, lacking moisture. It wasn’t until a team of researchers, using a new in vivo microscope technique called confocal laser endomicroscopy, discovered this layer while investigating a patient’s bile duct for cancer. They found that within this fuzzy layer are microscopic subcompartments of interstitial fluid (aka lymph fluid) that wrap around the entire body and connect into the lymphatic system. The lymphatic system connection that the interstitium has could be a key player in cancer metastasis [3].

Just like the other organs in our body, there are ways to keep this newly defined interstitium healthy and strong so it can continue to act as a shock absorber (because of the rebound properties) and help protect you from damage.

How to Keep It Healthy

1. Yoga:

Taking part in a yoga class works many different areas of the body from the cardiovascular system to the muscular system and everything in between. To focus in on the interstitium during your practice, pay attention to longer holds of poses and work into a gentle “bounce and recoil” within these holds.

For example if you’re in low lunge, pretend your back leg is a rubber band and deepen your stretch to your body’s most comfortable depth and then let your body rebound naturally to the natural lunge stance. Try not to control the rebound but let the body’s natural elasticity bring you back to the starting pose – thus working the elastic properties of the interstitium.

2. Myofascial Release Techniques (MFR):

MFR is a great way to work the interstitium as well as multiple fascial lines throughout the body. As an example, while standing, take a tennis ball or lacrosse ball and place it underneath the middle of your foot. Then, roll the ball from the base of the heel to the toes in a straight line. Next move the ball to the outer side of your same foot and repeat rolling in a straight line from heel to toes.

Move the ball to the inner side of the foot and repeat once more from heel to toes. After you’ve rolled the middle, outer, and inner sides of the foot, go back to a spot that felt it needed more work, place the ball under that spot and set your heel down. Wrap and unwrap your toes around the ball. Repeat on as many spots as needed then switch and repeat on other foot. This can be done throughout the entire body in a variety of ways and will reduce and eliminate restrictions.

3. Water:

Drinking water will help keep the moisture and elastic properties of your fascia, including the interstitium. Try to get at least eight – 8 oz. glasses of water each day to help keep your body and interstitium at peak function.


  1. Wiig, H; Swartz, M. A (2012). “Interstitial fluid and lymph formation and transport: Physiological regulation and roles in inflammation and cancer”. Retrieved April 11, 2018 from Physiological Reviews https://www.physiology.org/doi/full/10.1152/physrev.00037.2011
  2. Hedley, Gil – Somanaut (2018, March 28). “Interstitium aka: Perifascia: Gil Hedley dissects “the fuzz” on camera.1” [Video File] Retrieved April 11, 2018 from Youtube https://www.youtube.com/watch?time_continue=407&v=gf_2TSnlagM
  3. Olena, Abby (2018). “Is the Interstitium Really a New Organ?”. Retrieved April 11, 2018 from The Scientist https://www.the-scientist.com/ articles.view/articleNo/52168/title/Is-the-Interstitium-Really-a-New-Organ

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