Leonardo’s fascination with anatomical studies began while he was still in his late teens or early 20s and continued throughout the rest of his life. Although the date of Leonardo’s initial involvement with the study is unknown, it is believed that his interest in anatomy was sparked during his apprenticeship in Verrocchio’s workshop. This might have been in response to his master’s interest in anatomy or that of Verrocchio’s neighbor Pollaiuolo, who was renowned for his fascination with the workings of the human body. Nor can it be determined exactly when Leonardo began to perform dissections. It was more than likely after he moved to Milan, which at the time was one of the centers of medical practice and investigation into the workings of the human body. Regardless of the actual dates, his study of anatomy, originally pursued for his training as an artist, had grown by the 1490s into an independent area of research. As his sharp eye uncovered the structure of the human body, Leonardo became fascinated by the figura istrumentale dell’ omo (man’s instrumental figure) and he sought to understand its physical working as a creation of nature.
First it is necessary to lay to rest a myth about dissection of the human body in northern Italy. It did not violate Church doctrine and was not punishable as a crime. Bologna, the center of medical research in Europe from the 13th century onward, routinely had students of medicine participate in dissection. By the time of Leonardo’s birth, the practice was well-established. His interest in anatomy was not unique and was no doubt a product of the time and location – the late 15th century in northern Italy. In addition to the medical research in Bologna, the artistic movement in Florence and the engineering movement in Milan created a wave of interest in the workings of the human body. Artists wanted to study its form to accurately present it in paintings and sculpture. Engineers marveled at its structure and movement. It was during this period that there was a significant increase in physiological research and understanding. At the apex was Leonardo. How he recorded his findings was unique and revolutionary.
During the last decade of the 15th century and first decade of the next, Leonardo did practical work in anatomy on the dissection table in Milan, then at hospitals in Florence, Rome and Pavia, where he collaborated with the physician-anatomist Marcantonio della Torre. By his own count, Leonardo dissected 30 corpses in his lifetime.
His early anatomical studies dealt chiefly with the skeleton and muscles, but even at the outset, he combined anatomical with physiological research. From observing the structure, Leonardo studied the role of individual parts of the body and their mechanical activity. This led him to the study of the internal organs. Among those that fascinated him the most were the brain, heart and lungs; in his view these were the ‘motors’ of the senses and of life itself.
Leonardo’s findings were recorded in his now famous anatomical drawings. The images are among the most significant achievements of Renaissance science. The drawings are based on a connection between natural and abstract representation. He presented parts of the body in (transparent) layers that afford an insight into the organ by using sections in perspective. We now view such sectional drawings as integral to the learning process and it was Leonardo who was the first to accurately create these perspectives. He emphasized in his notes that the drawings were superior to descriptive words. He was of course correct; his anatomical studies have forged the basic principles of modern scientific illustration.
During his lifetime, Leonardo’s medical investigations remained private. He did not consider himself a professional in the field of anatomy and he neither taught nor published his findings, but he did publish some of his observations on human proportion. Working with his good friend, mathematician Luca Pacioli, Leonardo considered the proportional theories of Vitruvius, a Roman architect from the first century BC. Imposing the principles of geometry on the configuration of the human body, he demonstrated that the ideal proportion of the human figure corresponds with the forms of the circle and the square. In his illustration of this theory, the world-famous Vitruvian Man, Leonardo demonstrated that when a man places his feet firmly on the ground and stretches out his arms, he can be contained within the four lines of a square, but when in a spread-eagle position, he can be inscribed in a circle.
As much as Leonardo made strenuous efforts to become proficient across a wide range of topics and disciplines, throughout his life he remained an empiricist of visual observation. It is precisely through his observations and genius that he developed a unique theory of knowledge, where art and science formed a synthesis. His intellectual powers – self-contained and inherent in every one of his creations, was a force that continues to spark both interest and creativity today – five centuries after his passing.