972 



A MANUAL OF ANATOMY 



left pulmonary arteries convey it to the lungs, and in passing through 

 the pulmonary capillaries it is oxygenated and becomes arterial 

 blood. It is then taken up by the pulmonary venous radicles, and 

 conveyed to the pulmonary veins, which carry it to the left auricle 

 of the heart. From the left auricle it passes into the left ventricle, 

 whence it is driven into the aorta. The aorta and its various 

 ramifications convey the arterial blood to the different parts of 

 the body, and thereafter it is returned as venous blood to the right 

 auricle of the heart. 



Exterior of the Heart.— The exterior of the heart presents dis- 

 tinct indications of its division internally into four chambers. 



Superior Vena Cava 



Aorta 



Right Auricular Appendix-, 



Right Auric'e 



Right Coronary Artery 



.Pulmonary Artery 



,Conus Arteriosus 



(Infundibulum) 

 ,,- I>eft Auricular Appendix 



Left Ventricle 



. Left Coronary Artery 



Apex 



Fig. 397. — The Heart (Anterior View). 



These take the form of grooves, namely, auriculo-ventricular, 

 interauricular, and interventricular. 



- The auriculo-ventricular groove, which is deep, divides the heart 

 into auricular and ventricular portions, and it surrounds the organ 

 except in front, where the roots of the aorta and pulmonary artery 

 are situated. The auricular portion is posterior and sujx'rior in 

 jwsition, whilst the ventricular portion is anterior and inferior. 

 The right half of the auriculo-ventricular groove contains (1) the 

 right coronary artery, and (2) the right or small cardiac vein, which 

 latter lies chiefly in its posterior part. The left half of the auriculo- 

 ventricular groove contains (i) the transverse branch of the left 

 coronary artery, {2) the transverse branch of the right coronary 



