The mesentery: A ‘new’ organ you didn’t know you had

In case you’ve ever wondered what connects your intestine to your abdomen, there’s a word — and now, a single organ — for that: the mesentery. But don’t worry; you haven’t grown a new organ. It’s always been there, performing important functions that affect systems throughout the body, from cardiovascular to immunological.
Leonardo da Vinci depicted it as one contiguous organ, and it remained that way for centuries until 1885, when Sir Frederick Treves’ findings presented the mesentery as fragmented amongst the small intestine, transverse colon and sigmoid colon.