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

Unequal breadth

The cartilage [c. costalis] of the first rib is the broadest, as the first rib also excels the others in breadth; the second and third follow this one. The twelfth and eleventh [costae fluitantes XI-XII] are the thinnest of all, and also end in the thinnest cartilages. The middle ribs are of a middle nature, their cartilages becoming wider in their progress away from the bony substance of the rib. 46 For although the cartilages of the six upper ribs form intervals [spatium intercostale] and are equally separated from each other along their entire course, cartilages of the sixth, seventh, eighth, and ninth ribs become from time to time variously broad over their course, and as they join together they fill the intervals between them with their own substance (I, I in fig. 1). The cartilages of the five false ribs [costae spuriae VIII-XII] end in a sharp point (F in fig. 1), unlike the cartilages of the true ribs [costae verae I-VII]. The cartilage of the first rib, firmly attached at its end to the pectoral bone (C in fig. 1) [articulatio sternocostalis I], is wider than where it starts from the rib’s bony substance. The cartilages of the second, third, and three subsequent ribs narrow slightly as they progress, and each ends in a tubercle 47 (D in fig. 1; E in fig. 3) where we shall presently explain they are articulated to the pectoral bone.



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