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 16 On the Vertebrae of the Thorax

Variety based upon the substance of the vertebrae

Finally, a certain variety accrues to the bodies of thoracic vertebrae also with respect to their substance; for the larger and bulkier the body of each vertebra the less solid it is, but porous and distinguished with a random series of many foramina [ff. vascularia] in various shapes and sizes, through which veins and arteries enter to nourish the vertebral bodies. For unless twigs of the vessels make their way into the substance of the thick bones, it is impossible for the middle and inmost substance that is remotest from the surface to draw in nourishment (since it is so distant). Among the foramina of this kind, none are easier to see than the ones in the posterior surface of the vertebral bodies that faces the dorsal medulla (G in figs. 2, 3, 4). Here in most vertebrae a single special foramen is seen, large in proportion to the mass of the vertebra, rough, and ending in many small foramina [canalis nutriens]. 21 Though Galen appears to have ascribed such foramina only to the lumbar vertebrae, 22 if one carefully inspects each one he will see that the first lumbar, the twelfth and eleventh thoracic, and some vertebrae above them put forth these foramina, more conspicuous, more numerous, and deeper in proportion to the magnitude of the vertebrae, and that the body of these vertebrae is more porous than all the rest. This is because they are large vertebrae, do not have the trunk of the hollow vein (z to o in the fig. preceding ch. 6, Bk. 3) 23 resting on them, 24 and are wound only with the branches of the unpaired vein (F and later G in the same fig.). 25



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 16 On the Vertebrae of the Thorax