THE VASCULAR SYSTEM. 



to the bone. By separating the tibialis anticus and ex- 

 tensor longus digitorum muscles, this artery is well 

 displayed. Near the knee-joint a small branch, the 

 peroneal, is given off, and passes to the dorsal aspect 

 of the foot, where it anas- 

 tomoses with the dorsal 

 branch of the saphenous, 

 forming a superficial arch 

 sending branches to the dig- 

 its. The peroneal is so small 

 that it is frequently not in- 

 jected. In the tarsal region 

 two branches, an external 

 malleolar and an internal 

 malleolar, are given off. A 

 centimeter or two distal to 

 the latter branch, the main 

 artery passes between the 

 second and third metatar- 

 sals to the deep plantar re- 

 gion, where it receives an 

 anastomosing branch from 

 the saphenous, and sends 

 off branches to the digits. 



en 



FIG. 74. CROSS-SECTION OF AR- 

 TERY AND VEIN. X 350. 



V, Vein; .4, artery; 01, inner coat; 

 cp, epithelium lining the vessels ; 

 et, middle or muscular coat of 

 vein ; ex, muscular coat of artery ; 

 fb, fibro-areolar coat. - - (From 

 Martin's "Human Body.") 



THE VENOUS SYSTEM. 



The veins are the vessels 

 returning the blood to the 



heart. As a rule, veins carry only impure blood, but 

 the pulmonary veins returning blood from the lungs to 

 the left auricle carry pure blood. After death the veins 

 can readily be distinguished from the arteries by the 

 fact that they have much thinner walls than the arteries 



