andreas vesaliusAndreas Vesalius (1514-1564 AD)
Vesalius is widely considered to be the founder of the modern science of anatomy. He was a major figure of the Scientific Revolution. His book On the Structure of the Human Body is one of the most important early works on human anatomy.

At the beginning of the Renaissance, the ancient Greek physician Galen (130-200 AD) was the leading authority on anatomy in the ancient world. Galen worked at a time when Roman law forbade the dissection of human bodies. Therefore, he had to study anatomy by dissecting pigs and other animals to gain insight in to the human body.

Vesalius realized Galen's work unreliable, i.e. you could not gain an understanding of the human body without actually dissecting humans. Just like in Galen's time there was a ban on dissecting people (this time enforced by the Catholic Church). Vesalius ignored the ban making and made enemies within the Church in the process.

Vesalius' work had a similar impact as Erasmus' on human understanding. By dissecting human bodies Vesalius disproved a number of traditional teachings about the human form:

For example, Vesalius demonstrated men and women have the same number of ribs. This might not seem all that important of a thing to prove to a modern audience; however, in the 16th century people believed the story of Adam and Eve was literally true, i.e. God used one of Adam's ribs to make Eve. The Church, therefore, taught that men had one less rib than women (a belief Vesalius disproved and which led to accusations of his being an atheist).

Vesalius' book On the Fabric of the Human Body contained over 200 anatomical illustrations. The book placed in to question several of Galen’s doctrines:

1). Galen taught that blood had the ability to flow between the ventricles of the heart (which is not the case). The right and left ventricles are specialized, i.e. the right side pumps blood from the heart to the lungs through the pulmonary artery while the left ventricle pumps blood from the heart to other parts of the body through the aorta.

2). Galen thought blood was created in the liver; however, we now know bones are responsible for making it.

3). Galen also taught that the mandible, or jaw bone, was made up of two bones (like the jaw of a dog). The jaw bone or mandible is only one bone.

Vesalius' book laid the groundwork for subsequent improvements in medical science that were to be made in the centuries to come.