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

Description of the first cervical vertebra

The first cervical vertebra is more solid and dense than all the other bones of the spine, but thinner along its longitude, and most unlike all the others in shape. It has the largest foramen (I in figs. 2, 3, 4) cut in it for the dorsal medulla, because the medulla is thickest here. Its body is carved out in its inner portion [arcus anterior atlantis] (K in figs. 2 and 3), and it shows a pocket [fovea dentis] (L in figs. 3 and 4) lightly scooped out in the posterior part of its body, which is covered with cartilage and receives the dens (g, n in fig. 5, G in figs. 6 [10] and 11) of the second vertebra. The body of the first vertebra is hollowed out with the intention that the tooth should be able to nest there into the first vertebra. 41 Lest the first vertebra, its body carved out in this manner and nearly lacking a body, 42 be rendered unduly weak and feeble, it is augmented with a certain process and tubercle [t. anterius] (M in figures 2 and 10) in its anterior part, by means of which it is thickened and made stronger; in addition, the tubercle itself is suited for receiving an insertion, that of the first pair of muscles 43 that move the spine. Such is the usefulness of this tubercle; but it is not extended so far that it prevents excessive flexion of the head or supports the head in its flexed position; or that it causes the bent head to be bent more quickly back upward and to the rear, as Galen incorrectly stated in the fourth book of De anatomicis administrandis. 44 For (to say nothing here about the motion of the head except to name the vertebra over which it occurs) the head can in no way be inclined to the point that the occipital bone touches this tubercle: so far is the mass of the head from being supported by it. 45 The first vertebra is strongest and thickest at the sides of the cavity [arcus interior atlantis] (K in figure 3) where it admits the tooth of the second, and on each side it shows a depression [massa lateralis atlantis, facies articularis superior] (N marks the right one in figures 2, 3, and 10) where the capitulum [condylus] of its own side of the occipital bone is received. These depressions, one on each side, are oblong to match those capitula perfectly (if you inspect their anterior and posterior portions, O and P respectively in figs. 2 and 3) 46 ; they turn upward at their outer sides (R in figs. 2 and 3) and are deep at the inner sides (Q in figs. 2 and 3), just as if both depressions had been cut away from a single deep, round cavity. For if you divided the socket of the hip or another bone possessed of a round socket and placed one part of it by each side of the first cervical vertebra where the cavities now are, they would look just like the depressions of this first vertebra. 47 Or


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if you imagined the depressions of the first vertebra joined together, you would see a single, round, deep cavity formed from the pair. You will see this even more clearly in the first neck vertebra of dogs and apes, as in those animals these depressions are higher or deeper, and the heads of their occipital bones more pronounced and sharper.



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