The Renaissance artist Michelangelo was fascinated by human anatomy. He dissected cadavers to study them and so gained an impressive depth of knowledge about the body that he used when painting the Sistine Chapel.

New research published in Clinical Anatomy suggests that Michelangelo’s attentiveness to anatomy might have been spurred by a larger interest in the golden ratio. Though he is not known to have used it, many other artists of his day — including Leonardo da Vinci and Albrecht Dürer — did. The geometric concept states that a perfect rectangle can be split into a square and a smaller rectangle that has the exact proportions as the larger one — mathematically expressed with the value of 1.6180. It’s often said to be the most appealing proportion in nature, and the human body is thought to illustrate it.

The study, titled “More Than A Neuroanatomical Representation in ‘The Creation of Adam’ by Michelangelo Buonarroti, A Representation of the Golden Ratio,” claims that Michelangelo’s Sistine Chapel fresco fits the ratio perfectly — so perfectly, it seems, that the artist had to have consciously used it. And that he did so in everything from the painting’s figures to its overall composition.

The researchers came to this conclusion by measuring the painting using Image Plus Pro Software. First they compared the distances between the edge of the most famous panel, “The Creation of Adam,” and its most “critical element” — the space where Adam and God’s fingers are about to meet. It was a perfect match. The point divided the panel into a golden rectangle, and when they compared it to the entire fresco, it formed a much larger golden rectangle as well.

Lead author Deivis de Campos writes that

the data presented here are compelling evidence that the [golden ratio], which is found in many biological structures and works of art by renowned artists, did not go unnoticed by Michelangelo. Given this discovery, it is assumed that the beauty and harmony found in all the works of Michelangelo may not be based solely on his anatomical knowledge. We believe that in all probability, Michelangelo knew that anatomical structures incorporating the [ratio] offer greater structural efficiency and, therefore, used the [ratio] to enhance the aesthetic quality of his works.

The discovery seems to at least anecdotally bolster the legitimacy of the golden ratio, which recently has been called into question. A Fast Company article published in April quoted Stanford University mathematician Keith Devlin as saying that it doesn’t actually exist in nature, since its decimal points go on forever, making it an irrational number. So while you can find approximations, you can’t find the real thing. If it seems a bit nit-picky, Devlin supported his point with evidence that students he surveyed, when shown different rectangles, rarely picked the golden one.

But it will be hard for many to ignore the example of the Sistine Chapel, which has dazzled visitors for centuries. At least they don’t seem to mind that it’s a few decimal points off.