Human anatomy studies, both in art and science, have been around for the longest time.  However, it was not as emphasized until the 16th century.  This time was known as The Renaissance.  The time when art and scientific development advanced at an incredible pace.  The human body and form was what became one of the main focuses, and artists took this as an opportunity to study the expressionism of movement.  It was a symbolic and personal area.  Anatomy and physiology in the medical field were used to study the naturalistic representation of the body through dissection.  It was also a way for artists to have a reference.  It was not until the 17th and 18th century that the focus changed from the human anatomy to more of portraits.