14 ELEMENTARY PHYSIOLOGY. 



Notice how broad and peculiarly formed these two 

 (3) bones are. The sacrum (1) bone is wedged 

 between these two bones at the back. 



BONES OF THE UPPER EXTREMITIES. 



The In examining the shoulder, we first notice 



shoulder, these two collar-bones (8). Their use is 

 to brace the shoulders properly apart ; so one end 

 rests against the breast-bone and the other against 

 the shoulder. Next comes the shoulder-blade. (16). 

 These are so broad to allow the attachment of some 

 very strong muscles of the upper part of the body. 

 The upper arm has one large bone called 



Tin* Vrm 



the humerus ( 1 ) . The radius ( 2 ) and the 

 ulna (3) are the bones of the lower arm. There 

 are eight roundish little bones in each wrist (4), five 

 longer ones in the middle of each hand (5), three 

 short bones in each finger (6, 9, 10) and two in each 

 thumb (7, 8). 



BONES OF THE LOWER EXTREMITIES. 



Here we meet the largest bone of the 



The Thigh. _ . , ,.. Tl . ,, .. . ,, 



skeleton (1). It is called the femur. 

 Observe the round shape of its upper end (a). This 

 is called the head of the femur. Moving in a hollow 

 place of this large bone (3) ,it forms the ball and socket 

 joint of the hip. Do not fail to notice how securely 

 the lower limbs are bound to the main body by these 

 numerous strong ligaments. 



