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 19 On the Bones of the Thorax

The course of the ribs

Nothing remains now to be added, except perhaps the course of the ribs, which is far different in the bones of the ribs than in their cartilages. When the rib bones [costae] (from a through c to f in figure 3) first leave the vertebrae, they slant downward to the posterior, and from here (from f to A in figure 3) they decline to the sides of the thorax, always obliquely downward towards the front until they end in cartilage extending in a curve upward to the anterior (from B to E in the same figure). Thus when the ribs first put forth cartilage [c. costalis] they bend in an arc and an angle more or less upward. This course of the ribs (see the skeletons, particularly the second) is evident not only in those which are attached to the pectoral bone, but also in all the rest with the possible exception of the twelfth, whose cartilage faces quite obscurely upward. This curvature is seen especially in the middle ribs, which is to say the sixth, seventh, eighth and ninth, while in the upper and lower ones it is more subtle. 77



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 19 On the Bones of the Thorax