CHAP, in.] SKELETON OF THE HEAD AND TRUNK. 



51 



of the "body," the "body" of the rib being all that portion 

 which is distal to, or beyond, the tubercle. This body (b) is 

 somewhat flattened from before backwards at its upper part, and 

 slightly expanded in the same direction at its distal end, the in- 

 tervening part being nearly cylindrical. It exhibits a faint indication 

 of a groove running along its hinder side, especially at the upper 

 part of its body. A little beyond the tubercle the bone makes a 

 sudden bend downwards (a). This part is termed the angle, and 

 it is behind it that the groove just mentioned is most distinctly 

 developed, while in front it exhibits a roughened line for muscular 

 attachment. 



The distal end of the bone is hollowed out into an oval pit (p), 

 and into this the sixth costal cartilage is inserted. 



A. First rib. 



B. Sixth rib. 



C. Thirteenth rib. 

 a. Angle. 



6. Body. 



Fig. 25. SIDE VIEW OF RIBS. 



c. Capitulum. 



11. Neck. 



p. Pit for costal cartilage. 



t. Tuberculuui. 



The other true ribs differ but slightly from the sixth, except as 

 to length, which decreases as we pass forwards or backwards from 

 the ninth, which is the longest rib. 



The first rib is the broadest of all (Fig. 25, A), especially towards 

 its proximal end. Its capitulum has but one articular surface. The 

 " angle " about coincides in position with the tuberculum. 



The false ribs decrease in length backwards, but the last rib is 

 longer than even the fourth true rib. 



The three foremost false ribs (the tenth, eleventh and twelfth) 

 are united together by their costal cartilages, but the thirteenth 

 rib ends freely, and is thence termed a floating rib. The last rib 

 (Fig. 25, C), has but a minute rudiment of a tuberculum or none, 

 and the capitula of the last three ribs have each but one articular 

 surface. 



