128 ANATOMY FOR NURSES. [Chap. X. 



supplied with valves than the veins of the upper limbs. The 

 deep veins accompany the arteries. The two largest superficial 

 veins are the internal or long saphenous, and the external or short 

 saphenous vein. The internal saphenous extends from the ankle 

 to within an inch and a half of Poupart's ligament. It lies 

 along the inner side of the leg and thigh, and terminates in the 

 femoral vein. The external saphenous arises from the sole of 

 the foot, and, passing up the back of the leg, ends in the deep 

 popliteal. 



Both the deep and superficial veins of the lower limbs pour 

 their contents into the external iliac. The blood is returned 

 from the pelvis by the internal iliac veins, which, uniting with 

 the external iliac, form the two common iliac veins. They 

 extend from the base of the sacrum to the fourth lumbar 

 vertebra, and then the two common iliacs unite to form the 

 inferior vena cava. 



The inferior or ascending vena cava returns the blood from 

 the lower limbs, pelvis, and abdomen. It begins at the junction 

 of the two common iliacs, and thence ascends along the right 

 side of the aorta, perforates the diaphragm, and terminates by 

 entering the right auricle of the heart. The inferior vena cava 

 receives many tributaries, the chief of which are the lumbar, 

 ovarian, renal, and hepatic veins. 



The pulmonary artery. — The pulmonary artery conveys the 

 dark venous blood from the right side of the heart to the 

 lungs. The main trunk is a short, wide vessel (diameter 

 30 mm.) which arises from the right ventricle and runs for 

 a distance of two inches backwards and upwards (vide Fig. 78). 

 Between the fifth and sixth dorsal vertebrse, it divides into 

 two branches, — the right and left pulmonary arteries, — which 

 pass to the right and left lungs. 



The pulmonary veins. — The pulmonary veins convey the red 

 arterial blood from the lungs to the left side of the heart. 

 They are usually four in number, two from each lung. The 

 two left veins frequently terminate in the left auricle by a 

 common opening. The pulmonary veins have no valves. 



