190 



HEALTH AND DISEASE 



Sternum or Breast-Bone (fig. 292). This is a long bone, suspended 

 from the dorsal spine by the ribs, the first eight of which articulate with 

 it. In early life it is made up of six distinct pieces, united by intervening 



1 Cariniform Cartilage. 



Fig. 292. Sternum 



s Ensiform Cartilage or Xiphoid Appendage. 3 Inferior Border, 

 articulation with lower extremities of Costal Cartilages. 



4 4 4 Cavities for 



cartilage or gristle. In front it is like the keel of a vessel, owing to the 

 projection of a flattened piece of cartilage (cariniform cartilage) which 

 curves upward and presents a sharpened border to the front, and below 

 for about two-thirds of its length. The posterior extremity is continued 



Fig. 293. Sternum and Costal Cartilages 

 ' Cariniform Cartilage. 2 Ensiform Cartilage. 3 -' Costal Cartilages. 



backward by a flat piece of cartilage, called the xiphoid or ensiform 

 cartilage, and along the superior part of each side of this bone are eight 

 depressions, which receive the inferior ends of the cartilages of the true 

 ribs to form so many synovial articulations or joints. 



