220 DETAILED SYNTHESIS. 



of two adjoining vertebrae, and in the substance between 

 them. 



342. From their union with the vertebrae THE BIBS 

 CURVE back and down, forming a joint with the trans- 

 verse process of the lower vertebrae (see Figs. 7 and 8, 

 PI. 16), after which they begin to make a circuit, sweep- 

 ing down and around, as shown by Pis. 12 and 13, form- 

 ing the frame of the chest, and standing out like levers 

 for mus*cles to seize upon and control the movements of 

 the spinal column and all its dependent parts. 



343. THE LENGTH OP THE RIBS increases from the 

 first to the eighth, and from it to the last they diminish. 



344. A CURIOUS GROOVE is found just within the 

 lower edge of the ribs, within which is lodged the costal 

 artery, that is thus admirably protected from injury, and 

 also kept warm. 



345. THE FRONT ENDS OF THE RIBS are continuous 

 with their cartilages, which increase in length from the 

 first to the seventh, and then diminish. 



346. THE INCLINATION OF THE RIB (costal) CARTI- 

 LAGES is down in case of the first, horizontal in case of 

 the second, and upward in case of the rest. 



347. THE JOINTS OF THE COSTAL CARTILAGES are, in 

 case of the first pair, immovable, they growing directly 

 to the breast-bone (Sternum) ; the next six pairs have 

 movable joints, and are bound by ligaments to the ster- 

 num (see Fig. 2, PL" 18) ; the next three pairs of car- 

 tilages are pointed and joined by continuation with 

 those above ; while the lower two are but tips to their 

 ribs, that are hence called free or floating ribs, since only 

 one end is fastened. 



348. THE STERNUM or breast-bone is in early life 

 composed of two bones and a cartilaginous point. The 

 former are soon ossified into one, and the point usually 

 follows in the same course by the prime of life. 



842. How do ? 343. What said ? 844. Where ? 845. How ? 84C. What 

 said ? 847. What said ? 848. What said ? 



