The Interstitium, the Largest Organ We Never Knew We Had

The new organ, he explained, was a thin layer of dense connective tissue throughout the body, sandwiched just under our skin and within the middle layer of every visceral organ. The organ also made up all the fascia, or the thin mesh of tissue separating every muscle and all the tissue around every vein and artery, from largest to smallest. What initially seemed to be a solid, dense, connective tissue layer was actually a complex network of fluid-filled cavities that are strong and flexible, yet so tiny and undiscerning that they escaped the attention of the brightest scientific minds for generations.

Source: thedailybeast.com