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Why Science Took 500 Years to Catch Up to Da Vinci?
Sometime between 1507 and 1508, in the dimly lit room of the hospital of Santa Maria Nuova in Florence, an elderly artist sat by a 100-year-old man. The man fell asleep in peace, with not a single groan to be heard. Leonardo da Vinci then took his knife, and after a few minutes, he opened the man's chest to find out "the cause of so sweet a death”. This led to the discovery of one of the world's first clinical descriptions of coronary artery disease and cirrhosis of the liver.
Da Vinci carried out more than 30 dissections of human bodies, completing thousands of manuscript pages with fine, mirror-writing left-hand script and exquisite, detail-packed drawings. His most revolutionary passion was the human heart.
Leonardo wasn't merely charting its chambers; he was also working out the fluid dynamics, demonstrating that it was a muscle, mapping out its four valves and working out how vortices of blood seal the aortic valve.
But modern medicine had not paid the slightest attention to his discoveries for almost five centuries.
Only through the use of MRI scanners, supercomputers, and new biomechanics by cardiologists in the late 20th and early 21st centuries could Leonardo da Vinci's discoveries of the workings of the heart be deciphered, giving mainstream medicine insights into the heart that it did not discover for another 500 years.
In this blog, we will be diving more deeply into the depths of Leonardo da Vinci's anatomical drawings.
Why Was It That Science Lagged Behind So Far?
A combination of ill fortune, institutional dogma, physics that wouldn't be developed for centuries, and Leonardo's own extreme oddballism—these are the main reasons why Leonardo’s discoveries went completely unnoticed.
A Paper Trail Frozen in Time.
The most obvious problem with da Vinci's anatomical knowledge is that people didn't have access to it. It didn't change the course of early medicine simply because it was there but unavailable.
Leonardo never published anything. Whereas, on the other hand, the anatomist Andreas Vesalius, who came a generation later, published his book De Humani Corporis Fabrica in 1543, changing the course of medicine.
Leonardo was a serial perfectionist. He considered his anatomical work a continuous work, always unfinished. His huge library of loose papers and bound notebooks was left to his faithful pupil, Francesco Melzi, when he passed away in France in 1519. Melzi held on to the papers with great care, but after his death, the papers were lost, stolen, and sold in parts.
Over time, a bound volume of Leonardo's anatomical drawings came into the possession of the British Royal Collection in 1690. There, in the dark vaults of Windsor Castle, the drawings were forgotten until the early 20th century. Medical science went ahead and developed through trial and error, and the blueprint of the heart was bound in leather in a royal library.
The Story Of Heresy Against Galen: Fighting 1,300 Years Of Dogma
It is possible that if Leonardo had published his work in his time, the doctors of the 16th century could not have accepted it.
This was for more than a thousand years in European medicine, which was dominated by the writings of Galen of Pergamum, a Roman physician of the 2nd century.
Galen's word was law. He taught that:
The focus of the vascular system was the liver, not the heart.
Tissues were constantly consuming blood, while food was constantly being produced, like a tide, rather than flowing around in the bloodstream.
Instead of being a muscle, the heart was a spiritual furnace which heated the body.
The solid central wall (septum) had “pores” through which blood flowed between the heart's ventricles.
Leonardo's study of anatomy was based on his eyes, his observation, not on old books. He was able to demonstrate that the heart was a muscle with four chambers. He followed the coronary arteries to find that the heart fed itself. One Galenic belief Leonardo never shook off was the idea of invisible 'pores' in the septum — he even drew them in, despite never observing them directly. It was Vesalius, not Leonardo, who later searched for those pores, found none, and openly broke with Galen on the point.
The logic of the 1500s was to accept anything Galen said. In the 1500s, challenging Galen was considered academic heresy. Leonardo was uneducated and not a reader of Latin. If he had shown his drawings to the academics of Padua or Bologna, they would probably have called his observations the delusions of a non-professional artist.
Leonardo Da Vinci Was an Engineer Analyzing an Engine (Before Engineering Existed)
Da Vinci heart sketches were read by 18th- and 19th-century physicians through the lens of the standard scientific perspective of biology. However, Leonardo was considering it from a fluid dynamics/hydraulic engineering perspective.
In Leonardo's early years, working for the Duke of Milan, he spent years designing canals, waterwheels, dams, and pumps before he began studying anatomy. After opening a heart, he discovered a hydraulic pump running on the same principles as river currents.
The Aortic Valve Mystery
Throughout Galen's lifetime (and for centuries to come), physicians treated the aortic valve as a swinging door that was forced open by the blood pressure and closed when the heart relaxed.
This didn't make sense to Leonardo, because a mechanical valve this way would leak, wear out, and tear.
To prove his theory, Leonardo built a physical model – a glass cast of an ox’s aorta. He fed grass seeds into the model and inserted water into it, and he was able to visualize the flow of water. His mind was blown when he saw what he saw.
When the blood is pumped out from the ventricle, it collides with the wider sinus at the root of the aorta. The blood doesn't flow straight through, but instead, it creates a vortex, which is a whirlpool. During relaxation of the heart, this swirling vortex can affect the paper-thin leaflets of the valve without causing any wear and tear, and snaps them shut instantly, preventing backflow.
In the late 1800s, when these doctors examined Leonardo's drawings of the swirling water seeds and vortex rings in the aorta, they believed that he was being poetic or artistic. They had no knowledge of the mathematics or the physics of fluid mechanics, so they did not realize that he was talking about hemodynamics.
The use of sophisticated dye-flow studies did not begin until 1968, when the Oxford engineers (Bellhouse & Bellhouse) presented proof for Leonardo's vortex theory. High-speed MRI scans, as per an MRI study published in 2014 (Bissell et al., European Heart Journal): Leonardo's hydrodynamics from the year 1500 were right.
Mystery of the Heart's “Snowflakes”
Things were more complicated than just the valves. A team of researchers from around the world reported back in August 2020 in Nature, a world-class journal, on a structural feature of the heart known as trabeculae carneae.
The inside of the ventricles of the heart is lined by a complex network of muscle fibers, called trabeculae, which form a fractal pattern. They resemble the tightly woven web or a snowflake design.
They were first drawn by Leonardo da Vinci in all the details of a man's life. He theorized that such odd muscular threads served to heat the blood and to assist in the contraction of the heart.
For 500 years, these inner muscular ridges were long dismissed as evolutionary leftovers, and their function was poorly understood, little more than a mere anatomical curiosity that serves little purpose.
AI was used to analyze genetic data and MRI scans (around 25,000 MRI Scans) in the 2020 Nature study. The result? The "deceptive" muscle threads drawn by Leonardo in 1510 are similar to the dimples on a golf ball. They prevent the heart from getting clogged and make the blood move through the heart with each heartbeat. Dysfunction in these fractals directly correlates to heart failure.
Here's to Leonardo, with a feather quill and a candle-lit corpse; he intuited what 21st-century bio-supercomputing has proven.
The Ultimate Renaissance Tragedy
Leonardo's anatomical drawings are a case of "what-ifs" in human history.
If his work had been published in his own lifetime, the field of cardiology would have leaped forward by almost 200 years. Systemic blood circulation was discovered by William Harvey in 1628, which was the beginning of modern medicine; it may have been discovered a hundred years earlier. Many lives would have been changed if there had been fewer cardiac misinterpretations.
Rather, Leonardo da Vinci was alone at a historic high and a landscape of human biology that none could see. He had the eye of a great painter, the mind of a hydraulic engineer, and the curiosity of a true scientist.
He was not just ahead of his time. He was living in a future that science would not reach at all for another half a millennium.
