Human musculature. Computer-enhanced version of drawings by Andreas Vesalius, showing the human muscular system in seven frontal views and one side view. Muscles of the body are progressively dissected from right to left. The muscles repre- sented here are skeletal (voluntary) muscles which are under direct conscious control. Skeletal muscles account for up to 45% of body weight. Andreas Vesalius was a Flemish anatomist (1514- 1564). These drawings come from his book: De Humani Corporis Fabrica (On the Structure of the Human Body) first published in 1543.