When it comes to anatomy, human bodies that were not the only anatomical references used to figure out how we worked. More often then not animals such as horses were first used to explain human anatomy. Because human dissections were frowned upon by the Church many early studies were done with large enough animals.
Carlo Ruini (1530 - 98) was one such artist to do so. His publication of Anatomia Del Cavallo (Anatomy of Horses) was not only used in the field of animal care, but also looked at for general ideas about the human body. And even though the Church was not against the dissection of animlas for medical purposes, there still were not a lot of anatomy prints of animals created during the 15th century.
In comparison to treaties of human organs, Ruini's woodcuts are stylized very similarly, except for a one distinction. More so than not the horses looked like they were in as much distress as the picture would suggest.
Other woodcuts such as the flayed horse directly resembled treaties by Vesalius, almost to the tee. The positioning the background and even the seemingly lack of distress seemed to be straight from Vesalius himself.