Leonardo da Vinci described it, but it took until a few years ago for scientists to begin to take seriously the possibility of an organ in the abdomen that had not previously been classified as one—just a couple months ago, two biologists have declared it to be an organ according to the prevailing standards of anatomy, and it looks like their claim will likely stick.

The new organ is called the mesentery, which is Latin for “in the middle of the intestines”; unsurprisingly, it can be found in the middle of our intestines. Until around 2012 it was thought to be a series of separate structures keeping the intestines attached to the abdominal wall, rather like a series of support girders.

In the November 2016 issue of The Lancet, Calvin Coffey and Peter O’Leary from the University of Limerick published “The Mesentery: Structure, Function, and Role in Disease,” which purported to examine “distinctive anatomical and functional features” that “justify designation of the mesentery as an organ.”

The classical anatomical description of the mesocolon is credited to British surgeon Sir Frederick Treves, surgeon to Queen Victoria, in 1885, three years before he became the first man to perform an appendectomy in England. If that name is familiar to you, it might be because he was featured as a character in Bernard Pomerance’s 1977 play The Elephant Man as well as the 1980 movie directed by David Lynch (Anthony Hopkins played Treves in the movie).
 

 
Coffey and O’Leary used complex microscopy work to confirm that the relevant structures of the mesocolon are in fact interconnected, in other words part of a single overall structure. The mesentery has now been added to the famous Gray’s Anatomy textbook and described in this new paper.

In a statement, Coffey asserted that “in the paper, which has been peer reviewed and assessed, we are now saying we have an organ in the body which hasn’t been acknowledged as such to date.”

A decade ago or so, laypersons the world over became outraged at the subtraction of Pluto from our solar system on the grounds that it was too small to be counted as a planet. One hopes that those same people will take solace in the addition of an organ to our bodily systems.
 

 
via IFL Science!