CHAP. IV.] 



THE SKELETON. 



25 



FIG. 10. THE CLAVICLE. 



more or less curved, which confers upon them a certain amount 

 of elasticity, and gives them a more graceful outline. 

 Long bones of upper extremity : 



Clavicle (collar bone) 2 



Humerus (arm) 2 



Ulna ' 2 I (forearm) 4 



Radius, 2 j v 



Metacarpus (palm of the hand) 10 



Phalanges (fingers) .' . . 28 



46 



The clavicle forms the anterior portion of the shoulder. It 

 articulates by its inner extremity with the sternum, and by its 



outer extrem- 

 ity with the 

 acromion pro- 

 cess l of the 

 scapula. In 



the female, the clavicle is generally less curved, 

 smoother, and more slender than in the male. In 

 those persons who perform considerable manual 

 labour, which brings into constant action the 

 muscles connected with this bone, it acquires 

 considerable bulk. 



The humerus is the longest and largest bone 

 of the upper limb. The upper extremity of the 

 bone consists of a rounded head joined to the 

 shaft by a constricted neck, and of two eminences 

 called the greater and lesser tuberosities. The rounded head ; gt, 

 head articulates with the glenoid cavity of the ^ at r ^_ 

 scapula. The constricted neck above the tuber- berosity;6,groove 

 osities is called the anatomical neck, and that 

 below the tuberosities, the surgical neck, from 

 its being often the seat of fracture. The lower extremity of the 



1 All eminences and projections of bones are termed processes, and these 

 processes were named by the early anatomists, either from their shape or use, 

 or from their fancied resemblance to some well-known object. It is well to look 

 up the meaning of these Greek or Latin words which are used so plentifully in 

 naming all parts of the skeleton ; the whole subject will become more interest- 

 ing, more readily understood, and more easily remembered. 



FIG. 17. THE 

 HUMERUS. a, 



