(Chapter 14) Footnote 1:

In this chapter, the contrast between the two editions of the Fabrica is unusually clear. Unlike earlier chapters, the 1543 version of this chapter is monolithically Galenic, being little more than a condensed paraphrase of Galen’s remarks on the spine in book twelve of De usu partium. Vesalius’ dependence on a single source and the relative simplicity of his Latin style are in sharp contrast to the richer content, greater independence, and more complicated sentence structures of the 1555 edition. The 1543 version of this chapter most likely reflects an earlier stage of Vesalius’ development, closer to the 1538 Tabulae sex than the preceding chapters of the 1543 Fabrica.