CARTILAGES OF THE RIBS. 113 



lages of the false or abdominal decrease, successively, in length 

 from the eighth to the twelfth, inclusively; the last is a mere 

 tip to the end of the rib. The breadth of the first cartilage is 

 considerable near the sternum; the succeeding ones are not so 

 large at this point. With the exception of the first three, the 

 costal extremities of the cartilages are larger than the sternal; 

 and they become more rounded as they advance to the latter. 

 The cartilages, in point of magnitude, generally, will be found 

 in proportion to the size of the ribs with which they articulate. 

 The sixth and seventh are joined together, and are spread ouc 

 at their middle, which gives there an increase of breadth, and 

 permits them to touch, and sometimes to coalesce. 



The first cartilage goes obliquely downwards in the direction 

 of the rib to which it belongs, in order to join the sternum. 

 The second and the third cartilages are nearly horizontal, but 

 inclining a little upwards in their progress; the fourth, fifth, 

 sixth, and seventh, pass, successively, more and more obliquely 

 upwards to the sternum, in consequence of the increasing length 

 of the ribs requiring them to traverse a longer space to reach 

 this bone. From the direction of tlae cartilages being oblique- 

 ly upwards, while that of the ribs is obliquely downwards, the 

 angle formed near the rib at the base of the c.irtilage, where the 

 latter begins first to turn upwards, is less obtuse in the lower 

 cartilages than in the upper. The obliquity of these cartilages 

 is also very manifest, by comparing them with the side of the 

 sternum: with it they form a very acute angle below, and a very 

 obtuse one above. 



The cartilages of the false ribs, successively, decrease in 

 length, to terminate in front by small tapering extremities. 

 The first is united by ligaments, somewhat closely, to the last 

 true or sternal, and is occasionally sent forwards fully to the 

 sternum. The others are united more loosely, in such a way 

 that the anterior extremity of the one lies agains^ the inferior 

 margin of that which is above. The eleventh and twelfth car- 

 tilages are generally too short to touch the ones above, they 

 therefore are fixed principally by a connexion with the abdomi- 

 nal muscles. Their ribs are much more moveable than any 

 others, and have been called floating, from that cause. 



There is some difference between the two extremities of the 

 cartilages; the posterior or costal is a small, convex, unequal 



10* 



