After millennia of dissection and classification of the components of the subject of mankind's greatest interest -- the Egyptians were recording results of anatomical investigations in 3000 BCE -- you wouldn't think there we had much in the way of innards left to find.
(The new one is called the mesentery. It joins your stomach to your small intestine and brings the human organ tally to 79.)
Its discovery is a salutary reminder that we are far off drawing a line under the sum of all knowledge -- perhaps even the sum of all our insides.
Orthodoxies we rely on are founded on the best information available at a particular point and stay sound only as long as that information remains correct.
We all know that it is cheaper to manufacture low-cost goods in China because its population of one billion creates an almost endless supply of labour that will ensure their wage costs remain lower -- it's known as the demographic dividend.
In fact, a combination of annual hikes in the Chinese minimum wage (raised 20% in some territories in 2015), near-stagnant pay rates in western countries, and increased costs for Chinese manufacturers to meet tighter environmental and yes, safety, regulations, are combining to ensure the dividend will not pay out much longer. Some economists predict cost parity between China and the US for low-ticket manufacturing within a few years.
Moore's law, which states that computing power -- or strictly the number of transistors per square inch on a chip - doubles every two years, has held true for more than 50 years. But not much longer; processor manufacturer Intel estimates it cannot be sustained past 2021 unless individual transistors can be shrunk below the size of hydrogen atoms.
In safety and health, orthodoxies have also changed in recent years. From the small ones, such as the belief you should keep your back straight and crouch when lifting a load from the ground, right up to the idea that focusing on driving down the number of small accidents will inevitably have a virtuous effect on an organisation's fatality or major injury rate.
That "trickle up" effect -- inferred from Heinrich's triangle, which stated a fixed proportional relationship between many low-level incidents and a few serious ones -- has not been forthcoming in most organisations. As a result, some have now issued strict "life saving" edicts about work at height and vehicle use to deal with fatal hazards.
It is important for all of us to check our received wisdom from time to time and see that it is still worth the reception. If long-held truths in a discipline as old as anatomy are still open to successful challenge, it's unlikely that all the tenets of one as young as occupational safety and health are going to remain set in stone.