Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them] | Chapter 15 On the Vertebrae of the Neck or Cervix

The head with the first vertebra above the second

This is how the structure of the first vertebra with the second is accomplished, 82 using two broad tuberosities on the second vertebra and two depressions on the first, and again another depression on the first to which the tuberculum of the dens is joined. I should prefer that this construction be learned rather from an actual examination of the things than from my less elegant than truthful description, so that it may be more quickly judged whether Galen stated accurately that we flex and extend the head over the second vertebra, or nod and indicate refusal in the manner of Thracians with these joints, 83 or whether I have wrongly asserted that the head is swiveled by these structures together with the first vertebra as if on an axle [i.e., horizontally] [articulatio atlanto-axialis mediana], and that there is absolutely no flexion and extension at this point, contrary to the opinion of Galen solemnly repeated in so many places. For if you scrutinize individual features in the construction of the bones, the second vertebra of the neck will remind you of a beam set in the earth to which we have attached an axle. The dens will be this axle; and the first vertebra, to which the head is joined when swiveled in this motion as if they were a single body, resembles another beam turned on the axle.

A is one pivot, B the other.


84 Or the first vertebra is comparable to the pivot attached to a door, and the second to the pivot which we see set in the wall. The ligament running transversely over the dens [l. transversum atlantis] clearly shows that the first vertebra is in no way bent above the second: only if the dens were not moving could the first vertebra be moved in flexion forward and backward. Who then doubts that this ligament holds the dens in the depression of the first vertebra [fovea dentis], and that no such looseness could with Galen be ascribed to it that it should allow the first vertebra to be moved anteriorly so far from contact with the dens that the head would experience true bending? Further, two names in Julius Pollux now come to my support, one of which fits the first vertebra, the other the second. The first is named e)pistrofeu/j, the second the a)/cwn. These names undoubtedly have come down from the ancients, who trained their sons in anatomy. 85 They meant by the latter name to imply the vertebra which remains still like an axle, above which the other is swiveled; by the former they meant the vertebra which is turned about as if on an axle. 86 Now this would certainly corroborate my view, according to which I have already stated often that the head is moved in rotation above the second vertebra [articulatio atlanto-axialis]. Celsus (besides the poets) is my authority that these terms have survived from the ancients before Galen: though the portion of his book where he explains the vertebrae of the neck is damaged, and he himself altered things he did not understand, as many interpreters of Galen have done, nevertheless he seems to have first taken that opinion which most closely approaches my own, and in fact truth itself, from some ancient source whence he translated his chapter “On the Bones” into Latin. 87 There is surely no need to recall all these things at greater length, since it is possible to look at the neck of a hare or a rabbit or a lamb or a kid while eating and see more clearly than light that the motion which is rotary is performed over the second vertebra; 88 then you will no longer wonder why Galen seeks such an expert listener, especially well trained in mathematics, in the twelfth book of De usu partium 89 when nobody doubts that an otherwise elegant and difficult description of some complexity is rendered the more difficult the less it is understood by the author, and the more he misunderstands the artifice of Nature which he set out to explain.



Book One -- The things that sustain and support the entire body, and what braces and attaches them all. [the bones and the ligaments that interconnect them] | Chapter 15 On the Vertebrae of the Neck or Cervix