ANGIOLOGY 



233 



THE Venous Trunks 



The venous blood enters the lungs from the right ventricle through 

 the two pulmonary arteries (Fig. 70, No. i and 2). 



The two pulmonary veins (Fig. 70, No. 9 and 10) collect the ar- 

 terial blood from the lungs, and empty it into the left auricle. 



There are three venae cavae which collect the systemic blood and 

 empty it into the right auricle. These venae cavae are two anterior 

 (Fig. 70, No. 37 and 38) and one posterior (Fig. 70, No. 8). 



Each anterior vena cava is formed by the union of a vena jugu- 

 laris, a vena vertebralis, and a vena subclavicularis (Fig. 63, No. 15). 



^• X-- 





Fig. 71. — Veins of the liver of a fowl, .i, Vena mesenterica communis. 

 2, Vena portalis propria. 3, Anterior vena mesentericuB. 4, Vena portalis dex- 

 ter, 5, Vena portalis sinister. 6, Posterior vena cava. 7, Celiac axis. 8, Base 

 of the heart. 9, The liver. 10, Hepatic veins. 



The jugular vein is formed by the union of the vena cephahca 

 anterior, and the vena cephalica posterior. 



The jugular vein (Fig. 62 , No -B i) passes along the side of the neck 

 and lies near the trachea, the esophagus, and the pneumogastric 

 nerve. Near the base of the skull the two jugular veins, the right 

 and the left, are connected by a transverse vein. By this anasto- 

 mosis part of the blood from the left jugular vein is sent into the 

 right. Therefore the right jugular vein is larger than the left. The 

 jugular veins collect the blood from the tongue region, the thyroid, 

 the esophagus, the trachea, the crop, and other structures along its 

 course through the cervical region. 



