The scientific contributions of Spanish Renaissance anatomists are little known internationally, but were the key to understanding current anatomy, especially the anatomical work of Juan Valverde de Amusco, "the Spanish Vesalius". This study shows that his anatomical work is original, and that it was a milestone for science and for the Spanish language. Located across from the Vesalius factory, where the Latin writing is academic and difficult to understand, stands the work of Valverde as the very first modern anatomy manual, written in simple and accurate Castilian. It was disseminated extensively throughout Europe, which facilitated knowledge for professional physicians, surgeons and artists. The anatomy of Juan Valverde should be considered as original, based on its contribution: (1) the use of scientific method in anatomy, (2) the development of Spanish as a scientific language, proving that this language is useful, convenient for conveying medical knowledge, and contributes in reaching greater numbers of professionals, (3) to introduce in scientific language the ideas of clarity, simplicity and rigor.

KEY WORDS: Anatomy; History; Juan Valverde; Vesalio.