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

Articulation of ribs to the vertebrae

Articulation to the vertebrae is not the same for all ribs. The nine upper ribs are attached with a double articulation (a, c in fig. 3), the eleventh and twelfth with a single articulation; the tenth is quite rarely attached to its vertebra with two joints, however differently it may have seemed to Galen, who taught that each rib is attached to the vertebrae by a double joint. 50 The ribs articulated by two nodes put forth two tubercles (one L, the other M in fig. 4): one [L] by which they are articulated into the depression (X, d in fig. 3) incised in the bodies of the vertebrae, the other [M] by which they are supported on the inner surface of the tip of the transverse process [facies articularis processus transversi]. These tubercles 51 [t. costae] correspond to the depressions [fovea] which we stated are carved in the vertebrae when we described their construction. The first rib is articulated by a round tubercle to the body of the first thoracic vertebra, and then ascends the transverse process of the same vertebra until it is articulated to its tip by means of the other capitulum or tubercle. The second rib and the seven after it are always articulated to the common depression of two vertebral bodies [fovea costalis superior, f. costalis inferior] by a capitulum which is not round but protuberant like an obtuse angle; they are attached to the transverse processes in the same way as the first rib, although here too a certain variation arises in the joints because the depressions are not carved out at the same spot in the transverse processes. This is because the transverse processes of the upper vertebrae have their depressions cut in the lower portion of their inner surface, but in the lower vertebrae they are in the upper portion (as we stated above against the view of Galen), and in the middle vertebrae they are in between. That the articulation of the ribs to the body of the vertebra is higher than that which the ribs effect to the transverse processes, as much higher as the tip of the transverse process is lower than the depression carved in the vertebral body, I believe goes without saying. The articulation of the three lower ribs, which takes place only on the body of the vertebrae and in depressions not as deeply hollowed out, occurs also with not very protuberant capitula (N in fig. 5). In this way the ribs are attached to the vertebrae. What type of joint 52 they form with the pectoral bone [sternum], and along what course they pass forward from the vertebrae, we shall find the opportunity to explain as soon as we have added the construction of the pectoral bone to our account. This would be truly easy to explain if the human bone corresponded to that of apes, dogs, calves, and suchlike animals.



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