Nicolaus Steno's New myology (1667) : rather than muscle, the motor fibre should be called animal's organ of movement / Troels Kardel.
Abstract:
Muscular movement is the result of fibre shortening. How did this basic insight arise? Based on several of his observations, Nicolaus Steno in 1664 and 1667 proposed that muscles shorten when fibres shorten, and that skeletal muscles consist of uniform motor fibres layered as pennate structures. The basis for a new myology was provided in a geometrical model of the movement of the muscles. But fibre shortening was incompatible with the dominant ancient theory of contraction by inflation that was favoured by Descartes and by Steno's contemporaries William Croone, Thomas Willis, John Mayow, and Giovanni Borelli due to their adherence to the Aristotelian axiom: Anything which moves is moved by something else. The inflation theory blindfolded researchers well into the eighteenth century for skeletal and heart muscles. When the shortening of motor fibres was eventually visualised by microscopy this inflation theory was no longer tenable. Steno's structural claim on skeletal muscles was also rejected by Borelliand by later commentators. Pennate muscles were only rarely displayed until 1981 when macro-anatomical studies showed the morphology of most skeletal muscles to be similar to that described by Steno. Steno's proposals on muscles have since become a commonplace in computer models applied in the study of human and animal motion.
Nuncius Vol. 23, fasc. 1 (2008), p. 37-64