BONES, MUSCLES, EXERCISE, AND REST. 



251 



and fingers. The shoulder-blade or scapula (Fig. XXXVII.) 

 is a broad, thin bone, of triangular shape. It lies flat on the 

 back of the chest, imbedded in the flesh, and held in its 



Fm. XXXVn. Shoulder-Blade, or Scapula. 



a, Socket for the head of the 

 bone of the upper arm. These 

 form the shoulder joint. 



6, Border of the shallow 

 socket. 



place by the muscles. It has no direct attachment to the 

 trunk, but at its upper and outer corner it is connected with 

 the collar-bone. At this upper and outer corner it has a 

 shallow socket for the head of the bone of the arm. 



The collar-bone or clavicle (Fig. XXXII. g-, g) extends 



FIG. XXXVIII. Bones of the Wrist. 



a, Radius. 

 6, Ulna. 



c, c, c, c, Bones of the wrist. 



d, d, d, d, Bones of the hand. 



e, Thumb. 



from the upper end of the breast-bone to the upper and outer 

 corner of the shoulder-l)lade. It keeps the shoulder in its 

 place. 



