As an artist, he used science to understand the human body. As an anatomist, he used art to illuminate secrets beneath the flesh.
Five hundred years after Leonardo da Vinci’s death, his anatomical drawings are as powerful and poignant as they were in his time. Their beauty is breathtaking, their accuracy a testament to the genius of an artist willing to go to extremes to depict the human form.
Gifts to science
About a dozen cadavers lie sealed in blue body bags on stainless steel tables in the anatomy lab at the Boston University School of Medicine. Trudy Van Houten unzips one of the bags to reveal the body of a tall, elderly man. Prepared with embalming fluids, the body is ready for dissection.
Van Houten, an assistant professor of anatomy and neurobiology at the school, has taught clinical anatomy for 30 years. She leans over the body, glasses perched on the edge of her nose.
Her young assistant passes her a scalpel. She makes a neat incision into the skin of the upper right arm. Minutes later, she uses forceps to lift the biceps brachii muscle, which extends between the shoulder and elbow. Next to her, a television monitor displays a magnified image of one of da Vinci's drawings of a dissected arm. The muscles appear long and lithe, shaded in with lines that blend into a yellowed background.
The scene is being filmed for the NOVA documentary “Decoding da Vinci,” which probes the mysteries behind some of da Vinci’s most brilliant work. “His depictions of the human body were beautiful,” Van Houten later says. “And so accurate that we can actually use them to teach.”
Van Houten insists images are critical in teaching anatomy. “It’s something that anyone who teaches anatomy faces,” she says. “You can’t teach it without pictures.”
And although educators can now draw on 3D imagery and other computer-based models, Van Houten prefers the real thing. “The best models we have are dissected human bodies,” she says.
The bodies are donated to the school through its anatomical gift program.
Hundreds of students dissect the bodies, working in groups of eight. “They dissect from skin to skeleton,” says the program’s director, Robert Bouchie. “We start with the back and limbs.”
After the dissections are done, Bouchie leads a memorial ceremony for each body, which is then cremated. He and the students place the body in a coffin. There is a moment of silence. Family of the deceased often attend, he says.
Bouchie returns cremains in person to a handful of families each year. He explains why. “You can’t send it UPS, you can’t send it FedEx,” he says. “You have to send it USPS.”
Bouchie recalls once being asked the value of packed cremains by a postal worker. He told her the package was priceless. “So the clerk said I had to declare a value of zero,” he says. “I wasn’t comfortable with that.”
Human dissection: A unique learning tool
Before the advent of modern imaging, dissections revealed the complicated inner workings of the human body when there was, perhaps, no other way. Da Vinci yearned to witness these mechanics for himself. Though he lacked any formal medical training, he is believed to have dissected more than 30 bodies in his lifetime.
Though human dissections date back to about the third century BCE, the first recorded public dissection took place around 1315, when Italian physician and anatomist Mondino de Luzzi performed a dissection on an executed criminal.
The seminal anatomical book collection “De Humani Corporis Fabrica” (On the Structure of the Human Body), by Flemish anatomist and physician Andreas Vesalius, was published in 1543. The books dispelled anatomical theories that had been entrenched since the second century. Vesalius, however, also pillaged cemeteries in search of corpses for dissection.
Grave-robbing became a serious problem in the 18th and 19th centuries in some parts of Europe as well as the United States, where African American graves were especially vulnerable. Iron coffins and cage-like structures, known as mortsafes, were used to protect graves from body snatchers in England and Scotland. In a notorious case, William Burke and William Hare murdered at least 16 people in Edinburgh, selling their bodies for dissection.
The British Parliament passed the Anatomy Act in 1832, which made it legal for medical schools to dissect unclaimed bodies from workhouses and hospitals. The law curbed the practice of body snatching in Britain but disproportionately affected the poor.
For centuries, laws in Europe and the United States allowed dissections of executed criminals. However, da Vinci was able to procure bodies from hospitals across Italy. In Florence, he befriended a centenarian who he then witnessed peacefully pass away.
He later dissected the man’s body. The study led to da Vinci’s very early description of arteriosclerosis.
Science meets art
He correctly described the heart as the center of the blood system and was the first to describe it as a muscle with four chambers. He discovered how small vortices of blood help shut the aortic valve, but because his scientific papers and anatomical drawings went unpublished for centuries, this mechanism wasn’t confirmed until the late 1960s.
“He started with an interest of understanding the body to improve his art,” explains “Decoding da Vinci” producer Doug Hamilton. “But he clearly went further. He clearly became fascinated by understanding the human body.”
Da Vinci often dissected by candlelight, taking left-handed, mirrored notes throughout the process. “There's no refrigeration, he's sometimes doing it in the dark of night,” says Hamilton. “It’s a messy, smelly business. And yet, when you look at his drawings they don't convey any of that. They convey the beauty of the body.”
More than 7,000 pages of Da Vinci’s notes and drawings still survive. A painter, sculptor, architect, and engineer, da Vinci made visionary drawings of a giant crossbow, a simplistic machine gun, winged flying machines, and a self-propelled cart—which some say is the first design of a self-driving vehicle. He also designed canal locks, buildings, and bridges.
Then there were masterpieces like “Mona Lisa,” “The Last Supper,” and “Vitruvian Man,” a drawing that perfectly illustrates the fusion of art and science in da Vinci’s work.
Leonardo didn’t draw distinctions between art and science the way we do today, Hamilton says. The documentary, he says, is “an extraordinary story of how his scientific understanding went beyond what he needed to know to paint.”
Tune in or stream “Decoding da Vinci” on November 13 at 9/8c on PBS to learn more about the science behind Leonardo da Vinci’s art.