ANATOMY OF THE HEART AND BLOOD-VESSELS. 215 



the corresponding lungs. Opening into the right auricle are 

 two great veins (see also Fig. 89), cs and ci, known re- 

 spectively as the upper and lower venae cavce, or " hollow " 

 veins; so called by the older anatomists because they are 

 frequently found empty after death. Into the back of the 

 right auricle opens also another vein, Vc, called the coronary 



\d 



FIG. 90. The heart and the great blood-vessel attached to it. seen from the 

 .vanisthe sternum. The left cavities and the vessels connected with them 

 are colored red; the right black. Aid, right auricle; Adx and As, the right and 

 left aariculaf appendages; Vd, right ventricle; Vs, left ventricle; Act, aorta; Ab, 

 inn. -ruinate artery; Cs, left common cjfrotid artery ;"Ssft left subclavian artery; 

 P, i tain trunk of the pulmonary artery, and Pd and Ps, its branches to the right 

 and left lungs; cs, superior vena cava; Adt and A si, the right and left innominate 

 veins; pd and ps, the right and left pulmonary veins; crd and crs, the right and 

 left Coronary arteries. 



or sinus, which brings back blood that has circulated 

 in tlie wall? of the heart itsfclf. Springing from the left ven- 

 tricle, am 1 appearing from beneath the pulmonary artery 

 tae heart is looked; at from the ventral side, is a great 



,, th aorta. Aa. It forms an arch over the base of the 

 heart and then runs down be* ind it at the back -of the chest. 

 Fron< Mio . mvexity of the arch of the aorta several great 



