Despite knowing all we possibly can about the human body, it still continues to surprise and marvel in new ways.

Scientists have classified a new organ, called the ‘mesentery’, that could have major implications for how we treat gastrointestinal diseases.

In a review paper published in medical journal The Lancet Gastroenterology and Hepatology, surgeons Professor J Calvin Coffey and Dr Peter O’Leary from the University of Limerick in Ireland have attempted to correct hundreds of years of medical orthodoxy with their discovery.

“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,” Professor Coffey said in a statement.

Up until recently, this organ was thought to have just been a number of disconnected structures – the transverse mesocolon, the sigmoid mesocolon, the mesoappendix and the mesorectum – but it turns out that they are all one, continuous organ.

“The anatomic description that had been laid over 100 years of anatomy was incorrect,” Professor Coffey said.

“Up to now there was no such field as mesenteric science. Now we have established anatomy and structure.”

The mesentery consists of a double folding of the peritoneum, or lining of the abdominal cavity, that attaches the intestines to the wall of the abdomen and acts as an anchor that keeps things in place.

Its function, on the other hand, still remains a mystery so further research is crucial to determining its role (if any) in abdominal and gastrointestinal diseases – once a baseline of normal function is established, this will help scientists determine what impact (if any) abnormal function has on various diseases and disorders.

For example, scientists have observed that in patients with Crohn’s disease the mesentery is often thickened and ‘creeping’ mesenteric fat could play an active role in disease development and progression.

“When we approach it like every other organ … we can categorise abdominal disease in terms of this organ.”

However, Sydney doctor and host of Embarrassing Bodies Down Under, Brad McKay, cautioned against overshooting the significance of the classification.

Dr Brad McKay says we shouldn’t hype up the discovery too much. Photo: Instagram

“We’ve known about the mesentery for centuries, but treating it as its own anatomical entity may help us further our understanding of the complex causes of disease, or it might not,” Dr McKay told The New Daily.

“It depends on what we find in further research.”

He said if researchers discover unique receptors on cells within the mesentery, then there is potential for their function to be moderated by targeting them with novel drugs.

But he questioned whether it should be studied separately to gastroenterology.

“I don’t think patients will start booking in to see their mesenterologist anytime soon,” Dr McKay said.

“Whatever we find will probably be encompassed under the umbrella of seeing a gastroenterologist.”

The first documented description of the mesentery was actually made by Leonardo da Vinci, who “drew the mesenteric organ as a contiguous structure”, but it was not seen as a single entity until another study by Coffey in 2012.

Since then, the discovery has prompted updates in medical textbooks, including the well-known Gray’s Anatomy.

The last time a new body structure was identified was in 2013 when surgeons from the University Hospitals Leuven in Belgium discovered the anterolateral ligament in the knee.