Leonardo da Vinci’s famous drawing of the Vitruvian Man, created around 1490, has for centuries symbolized the balance between art, science, and geometry. Inspired by the writings of the Roman architect Vitruvius, the figure depicts the human body inscribed within a circle and a square. Only recently, however, has a previously unnoticed detail been identified: at the groin level, there is the trace of a hidden equilateral triangle, which could solve the mystery of Leonardo’s proportions.
According to Rory Mac Sweeney, a researcher at Trinity College Dublin, the equilateral triangle outlined between the figure’s legs, evoked in Leonardo’s notes, explains why the figure’s specific proportions suggest a nearly perfect relationship between height and body width. Calculations show a ratio between the height to the navel and the distance between the feet of between 1.64 and 1.65, very close to the famous tetrahedral ratio of 1.633, discovered only in 1917 and also used in dentistry (Bonwill’s triangle) and spatial geometry.
This discovery suggests that Leonardo, in his drawing, may have already intuited advanced mathematical principles centuries before their formal codification. Rather than relying solely on the golden ratio, famously associated with the work, Leonardo may have employed more complex geometric ratios, intuiting how human anatomy is organized according to universal mathematical laws.
From a traditional Renaissance manifesto in which man is “the measure of all things,” at least as Vitruvius maintained, the Vitruvian Man is today enriched with new meanings. The identification of the triangle is a surprise both scientific and iconographic: the drawing not only reflects an ancient aesthetic canon, but incorporates a precise mathematical code, anticipating modern insights into the nature of human proportion.
Leonardo da Vinci, with his unique ability to combine artistic observation and scientific rigor, continues to amaze us even five hundred years later. The mystery unveiled in the groin of the Vitruvian Man adds a new dimension to understanding the work, transforming a famous drawing into a testament to the universal geometric thought of the Renaissance.
