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 protuberances of the second vertebra

These depressions are coated with cartilage and receive two tubercles 61 (the right one is c in figures 5 and 6; the left is d, e, f) of the second vertebra of the neck, which are located near the side of the vertebra’s body and protrude very slightly, just as the depressions of the first vertebra are lightly hollowed out. 62 The outline of the tubercles is also round like that of the depressions, though at the same time it is seen to stretch out a little in the posterior part (f in figures 5, 6) beyond the circumference of a circle. Also, the inner side of the protuberances (d in figures 5 and 6) rises higher than the outer side (e in figures 5 and 6), but this height and depression of the sides is not as conspicuous as that of the brows on the depressions of the first cervical vertebra, and the swellings in the middle or center are not as high as the depressions between the brows of the first vertebra are deep, exactly as if the sides of the swellings rose higher than their middle. Consequently, in bare bones fitted together the depressions do not exactly match the tuberosities, and the space in the middle of those depressions does not appear quite filled. This occurs only in humans: in dogs and horses and other animals that turn their head a great deal further, there is a single continuous tubercle on each side of the second vertebra, and the depression also appears continuous in the first cervical vertebra, closely matching the tubercle. Nature often corrects this inequality in humans with a special cartilage 63 that, in addition to the cartilage [hyaline] attached to the bones like a crust, comes between the depression and the tuberosity and grows only on the ligaments 64 containing the joint 65 in the circle; it is coated above and below with a rather viscous humor [synovia] like an ointment. Such then is the double attachment (one on each side) of the depressions of the first vertebra with the tuberosities of the second, created for the sake of the motion which I shall presently relate.

Here we have drawn the special cartilage on each side which we have sometimes observed.




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