Scientists Map the Interstitium, a Hidden Network of Fluid-Filled Pathways in the Human Body

For centuries, the human body was believed to be fully charted — yet hidden within its very tissues lay an entire fluid network, invisible to the tools we trusted most. Researchers have now revealed the interstitium, a vast web of fluid-filled spaces woven through nearly every organ and tissue, only made visible through imaging techniques that preserve the body in its living state. This discovery does not merely add a footnote to anatomy; it reframes how disease travels, how immunity moves, and how much of the familiar can still hold profound secrets.