[Nicolaus Steno's geometrical description of muscle: the investigation of muscle movements in the 17th century].

Famous geologist Nicolaus Steno (1638-1686) was known as a skillful anatomist in his time. His main work about anatomy is "Elementorum myologiae specimen, seu musculi descriptio geometrica". Steno introduced geometrical representation into muscle study. His purpose was to handle muscle movements in the style of Cartesian mechanical philosophy, assuming muscle fibers as the structural and functional unit of muscle. Steno modelled muscles as parallelepiped integrations of fibers. Steno thought the shortening of muscle fibers modified parallelepiped integration and its modification resulted in muscle movements. His parallelepiped model enabled the regarding of muscles as objects of physics. Steno's assumption and model built a methodological foundation of mechanistic physiology of muscle, and influenced latter 17th century thinkers, especially Borelli.