Final answer:
Andreas Vesalius obtained his detailed drawings of the human body through the dissection of human cadavers. His work was critical in advancing the field of anatomy during the Renaissance period, as it provided a clearer and more accurate depiction of the body's internal structures than had been available before. Legal changes allowed for the use of corpses of criminals or donated bodies for dissection, aiding Vesalius's efforts.
Step-by-step explanation:
Andreas Vesalius is renowned for his contributions to the study of human anatomy during the Renaissance period. He obtained detailed drawings of the human body through direct observation by performing dissections of human cadavers, which was a controversial practice at the time. Before the widespread practice of human dissection in medical schools, knowledge of internal anatomy was limited and often inaccurate. Vesalius was among the pioneers who challenged prevailing notions by meticulously studying the body's internal structures.
Laws were eventually passed that permitted the dissection of the bodies of criminals and those who donated their bodies for scientific research. These legal changes allowed Vesalius to dissect legally obtained cadavers rather than having to resort to methods such as grave robbing. His dissections enabled him to create elaborate and detailed illustrations, greatly advancing the field of anatomy. These illustrations were particularly significant at a time when surgeries were infrequent and there were no non-surgical methods available to study the internal structures of the living body.
It wasn't until much later, in the late nineteenth century, that medical researchers discovered non-surgical methods, such as X-Rays, to look inside the living body. Vesalius's work laid the foundation for these later developments and transformed how the human body was understood and studied.