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 22 On the Clavicles

Their articulation to the pectoral bone

The clavicles are articulated to the pectoral bone [manubrium sterni] by depressions [incisura clavicularis] (r in fig. 7, ch. 19) which we have said are carved out in the sides of the topmost part of the first bone. Just as those depressions are oblong, running from the anterior parts posteriorly downward, wider on the anterior than the posterior, and higher on the inner side than on the outer, so also are the heads of the clavicles [extremitas sternalis] (A in figs. 1, 2, 3) which are connected to the pectoral bone. These are oblong like the depressions 8 [facies articularis sternalis], and depressed; if one paid careful attention to their circumference, he would judge that it is more or less triangular. One angle (B in fig. 1) is in the anterior part of the head toward the bottom, quite blunt. The second (C in figs. 1, 2, 3) is also blunt, visible in the upper part of the head somewhat toward the posterior. The third (D in figs. 1, 2, 3) is more acute and longer, located in the posterior region and angled downward. As these angles are obtuse, the lines of the triangle are irregular and deflected outward. The one that runs from from the first angle to the second (from B to C in fig. 1) is the shortest; the one from the second angle to the third (from C to D in figs. 1, 2, 3) is much longer; the one from the first to the third (from B to D in fig. 1) is the longest of all, and curved. Such is the circumference of the clavicle’s head; it is coated with a large amount of cartilage [cartilago articularis], and smooth. But when the cartilage is broken away together with the very thin epiphysis, the head is rough and uneven.



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 22 On the Clavicles