Not sure if this will be an organ you ever complain to you doctor about or anything like that but thought it would be worth sharing just in case the day comes that this is brought up and you have no idea what they are talking about, well now you would know if this does become a 'mainstream' universally recognized organ of the human body. via Gizmodo: Anatomy books are in need of a major upgrade, argue a team of scientists in a paper published Tuesday in the journal Scientific Reports. They say the body contains a previously undiscovered network of fluid-filled pockets and collagen underneath the skin that covers most of the body and internal organs. More than that, the structure should be considered an organ itself. The proposed organ, christened the interstitium ("interstices" being a catch-all term for the space between the structures of the body), was discovered accidentally, the researchers say. They stumbled upon it while conducting routine endoscopies, a medical procedure that