Drawing muscles with diagrams: how a novel dissection cut inspired Nicolaus Steno's mathematical myology (1667)

Abstract

In 1667, twenty years before Isaac Newton published his mathematization of physics, and more than ten years before the publication of Giovanni Borelli's De motu animalium, the Danish anatomist Nicolaus Steno published an entirely new geometrical theory of muscle motion in the book Elementorum myologiæ specimen. Historians of science have studied this book in recent decades, but the recent rediscovery of a seventeenth-century muscle atlas at the Bibliothèque interuniversitaire de Santé in Paris sheds new light on the largely overlooked origin of Steno's mathematical theory of muscles. In this article, we show that Steno's muscle diagrams result from a tension that Steno faced when combining his interest in illustrations with presenting his mathematical insights about the inner structure of muscle fibres. Furthermore, we argue that Steno's diagrams are deeply connected to observations through a new method of dissecting the muscles. The observational origins of Steno's mathematical insight are further confirmed by the strong correlation between Steno's depictions of the structure and function of skeletal muscles and the results of current biomechanical investigations.