Male body anatomy, 15th century. Historical artwork of the human male body by the Italian artist, engineer and scientist Leonardo da Vinci (1452-1519). The sketch shows a sectional view of a standing male. The spine, spinal cord, thorax, ribs, intercostal nerves and muscles, and some blood vessels of the pelvis, thigh and trunk are shown. The sketch has been annotated with da Vinci's characteristic mirror writing. Leonardo wrote backwards, from right to left, but his writing can be read if viewed in a mirror. He also used his own abbreviations and no punctuation. This illegibility ensured that his work remained obscure until the late 19th century.