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 14 On the Spine and its Various Bones

That it was more suitable for the spine to bend forward

Now because it was not equally safe for the spine to bend forward and backward (for if so it would have been weak, unstable, and loose), Nature justly selected what is better. For all the tasks of life it is more practical that the spine bend forward; this flexion also brings less harm on the vessels resting on the spine at that point, such as the great artery [aorta] and the vena cava, since they are otherwise extended considerably. Therefore because it was necessary that the spine be precisely confined in its anterior portion, the vertebrae are deservedly jointed more loosely in their posterior part. We shall now add what form these joints take and what remains to be said about individual vertebrae. 36 For there are several differences in the vertebrae, showing the unbelievable skill of Nature throughout. For this reason they must be explained in no perfunctory or hurried way in the four chapters now to follow, of which the first will be dedicated to the vertebrae of the neck or cervix, the second to those of the thorax, the third to those that are in the loins [lumbar], and the fourth to the sacrum and coccyx.



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 14 On the Spine and its Various Bones