Leonardo da Vinci (1452-1519) was an Italian scholar who had expertise in various fields. Although Da Vinci is known for his unbelievable artistic works, he indeed made significant contributions to the scientific field. But most of his achievements were unknown even until 200 years after his death.
The training in anatomy that he did as a part of his artistic career built an interest that, in turn, led him to pursue independent research in anatomy. Da Vinci started dissecting corpses in the 1490s to learn about the construction and functioning of the human body. Before this, he dissected birds and animals and later compared them with the anatomy of the human body. In the period between 1498 and 1513, he dissected over 30 corpses of different ages and both genders. In those times, dissection was a tedious process because the methods to preserve bodies weren't yet discovered.
Da Vinci paid grave robbers to acquire corpses, as human corpse dissection was legalized only for medical universities and doctors who perform post-mortems to investigate the cause of unnatural death. However, during the 1500s, as he became a reputed person, he was allowed to dissect corpses in medical universities and hospitals.
Da Vinci initially emphasized the skeleton and muscles. While studying anatomical structures, Da Vinci was very keen to know their role in the functioning of the human body. Besides, he also wanted to know the roots of emotions and thoughts. With deep dissections that lead to the penetration of internal organs, Da Vinci recognized the brain, heart, and lungs as the most important structures in the human body. These structures were well portrayed in his three-dimensional anatomical drawings. He identified the heart as a muscle with four chambers.
In 1506, in Santa Maria Nuova Hospital in Florence, Italy, Da Vinci witnessed the death of a 100-year-old man. Soon after his death, Da Vinci started dissecting his body. He noted liver cirrhosis, and the arteries of the man were dry and shrunken. Also, when he compared this body with a two-year old's body, the findings were different.
The Vitruvius Man
Leonardo da Vinci collaborated with the mathematician Luca Pacioli to apply the proportional theory of the ancient Roman architect Vitruvius to the human body. Da Vinci proposed that the ideal configuration of the human body is in consonance with the square and circle, which resulted in the famous work 'the Vitruvius Man.' This was an attempt by Da Vinci to prove the link between humans and nature, as, during that time, the circle was considered cosmic and divine. In this drawing, Da Vinci illustrated a naked man inside a square and a circle with limbs in two different positions. 'The Vitruvius Man' is one of the famous paintings of Da Vinci, like Monalisa and the Last Supper.
In modern times
Even in today's world, many surgeons are in awe of Da Vinci's precise anatomical drawings. They claim that he was way ahead of his time and that his drawings are in accordance with medical philosophy. Several anatomical professors still use Da Vinci's anatomical drawings to teach medical students. His works are written in Italian in mirror handwriting. Apart from that, he was a lefty. Da Vinci's anatomical works are kept in the Royal Library in Windsor Castle, United Kingdom.
Sources:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3361109/
https://www.ajconline.org/article/S0002-9149(12)02610-0/fulltext
