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 18 On the Sacral Bone and the Coccyx

Foramina transmitting nerves in the sacrum

The foramina carved out in these six bones to carry nerves [nervi sacrales] (1-6 in figs. 1 and 2; better yet, see figs. 2 and 3 at the head of ch. 11, Bk. 4) in every way resemble in appearance, if not in number, those cut in the three canine bones [vertebrae sacrales I-III]. In the human, five are cut on each side of the anterior surface next to the joint of the bodies, and the same number in the posterior, so that these bones provide a path [foramen sacrale] for six pairs of nerves. The first pair [nervus lumbalis V, rami posteriores et anteriores] exits between the first sacral bone and the fifth lumbar vertebra, in the same way as the other nerves proceeding from the sides of the lumbar and thoracic vertebrae. The second pair [nervus sacralis II, rami posteriores et anteriores] exits between the first and second sacral bones; the others in this series come out in succession so that the emerging pair always takes its number from the bone beneath. Besides these foramina carved out for the nerves, others (e-k in fig. 2) appear in the posterior side of the sacrum between the spines of the bones, facing into the route [canalis sacralis] prepared for the dorsal medulla. 38 These foramina are filled with ligaments, just like the intervals and foramina visible between the spines of the other vertebrae.



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 18 On the Sacral Bone and the Coccyx