THE CIRCULATION. G9 



it descends. On a level with the top of the hip-bones, it 

 divides into two vessels, one of which supplies each of the 

 lower limbs. From the arch, branches are given off, 

 which supply the head and the arms. 



2, In the thigh, the large vessel which carries the main 

 stream is called the femoral artery. In the leg it is called 

 the tibial artery. 

 S 3, The carotid arteries carry the blood from the arch to 



/ the head. They pass up on each side of the neck, and 

 their throbbing can often be seen.^ The subclavian ar- 

 teries lie behind the collar-bones. They extend to the 

 armpit, and in that situation receive the name axillary. 

 From the armpit to the elbow they are called brachial. 

 At the elbow they divide into the radial and ulnar. The 



V radial lies on the thumb-side of the fore-arm, and is the 



\one in which the pulse is commonly felt. 



4, All the large arteries lie deep. They can be felt or 

 seen on the surface, only in a few places. But many large 

 veins lie just beneath the skin, and can be traced for some 

 distance. 



The deep veins run by the side of the arteries. 



5, The veins frequently have the same names as the 

 arteries which they accompany. Sometimes they have 

 special names. The large veins of the neck are called 

 jugular veins. The superficial jugular is the prominent 

 vein just beneath the skin on each side. 



6, The blood flows in the large arteries much more 

 rapidly than in the small ones. Its flow is slower in the 

 veins than in the arteries. It is slowest of all in the 

 capillaries. This is for the same reason for which a 

 stream flows more slowly when its channel is wide than 

 when it is narrow. The capillaries are very small; but 



