Only Skin Deep
Andreas Vesalius (1514 - 54) is one of the most noted scholars in the 15th century when it comes to understanding and portraying the human anatomy. His book De humani corporis fabrica (On the Fabric of the Human Body) contains dozens of detailed figures of study. His text would later become the standard for modern medicine in the 16th century.
These works are from his book and were at the time considered revolutionary with its never-before-seen way of observing the human body (1). The reason that his works where so realistic and accurate is because Vesalius performed many actual dissections in order to show how wrong earlier depictions of the human body where during that era (2).
One of the most noted aspects about his work, other than the strict attention to detail, is the stylized posing of each subject. Every flayed body looks as if they are taking a striking picture, unscathed and looking like they are enjoying themselves and the attention. It is a true contradiction to the eyes in how you see the subject and how you would think the someone in their conditions would look like.
(1) Domenico Laurenza, Art and Anatomy in Renaissance Italy: Images from a Scientific Revolution, translated by Frank Zichello (New York: Metropolitan Museum of Art, 2012)
(2) Karen Raber, Animal Bodies, Renaissance Culture (Philadelphia: University of Pennsylvannia Press, 2013)