THE CHEST. 



97 



rickets there is the prominent "pigeon" breast and the 

 rosary, that is, a bead at the juncture of each rib with 

 the costal cartilage, while in emphysema the chest is 

 enlarged in all directions and barrel-shaped. In severe 

 cases of lateral curvature it is distorted but may be im- 

 proved by exercises. 



The Sternum. The sternum or breast-bone is a long 

 narrow bone and has three parts, the manubrium or han- 

 dle above, the gladiolus or sword, and the ensiform 

 cartilage at the lower end. On either side are notches 

 for the costal cartilages; for the first seven ribs as well as 

 the clavicle articulate with it. Except for some muscles 

 along the edges it lies directly under the skin and the 

 ridge between the manubrium and the gladiolus can be 

 felt in the living, a fact which assists in determining the 

 position of the different ribs in cases of fracture, as the 

 second rib articulates at this point. 



FIG. 37. A and B, typical ribs; C, first rib; D, twelfth rib. 1, head; 2, neck; 

 3, tuberosity; 4, grooved edge; 5, shaft; 6, oval depression for costa cartilage. 



The Ribs. The ribs are twenty-four in number, 

 twelve on each side, of which the upper seven, which 

 articulate with the sternum by individual cartilages, are 

 called true ribs, the other five false ribs. Of the false ribs 

 the upper three articulate indirectly with the sternum 

 through the seventh cartilage, with which their cartilages 

 unite, while the other two have their anterior extremities 

 free and are called floating ribs. All the ribs slope down 

 7 



