(Chapter 16) Footnote 33:
Vesalius cites De ossibus in the margin. “The tenth ... is the only vertebra to have not only its upward apophyses but also its downward terminating in condyloid ends.” (§760, tr. Singer 1952 p. 772). In De usu partium 4.79.1ff. Galen describes the unique articulation which he ascribes to the tenth thoracic vertebra: “just as this vertebra has a special position and a special posterior outgrowth not shared with the others, so its articulations are special too; for in order that the whole spine might bend uniformly it was of course necessary for the middle vertebra to remain in place while all the others withdrew gradually from one another and from it, the upper ones retiring upward and the lower ones down.” (tr. May 1968, p. 588). This is what Vesalius means when he quotes Galen as saying this vertebra “is supported above and below,” supra infraque suscipi. But we are unable to find a passage in either of the Galenic works where it is stated that transverse processes in thoracic vertebrae 10-12 would have interfered with lateral motion of the spine.
In the 1555 edition Vesalius rewrote the parenthesis as follows: “Which Galen said is received from the adjacent vertebrae by its ascending and descending processes, as we shall say more explicitly a little later.”