THE HEART 



92; 



the points last named to the ends of the basal line. The right border consists 

 entirely of the right auricle, and the left of the left ventricle. 



Tlie position of the auriculo-ventricular sulcus is indicated by a line from the 

 third left costal cartili^ge to the sixth right. 



Size and weight. — In the adult the heart measures about five inches (125 

 mm. J from base to apex, three and a half inches (87 mm.) acnjss' where it is 

 broadest, and two and a lialf (62 nnn. ) at its thickest portion. In the male its 

 weight averages about eleven ounces, and in the female about nine ounces. It 

 increases both in size and weight up to advanced life, the increase being most 

 marked up to the age of twenty-nine years. 



Fig. 546. — Anterior View of the Heart with the Larger Vessels. 

 (By permissiou. Museum of the Royal College of Surgeons.) 



Left common 



carotid artery 



Right superior thyroid vein Lfjt superior | 



Right common carotid artery 



Internal Jugular vein 



Vertebral vein 



Internal jugular vein 



Left vertebral rein 



i 



Subclavian vein 

 Inferior thyroid veins 



I'ena azygos major 



Vena cava superior 



Aorta 



Right pulmonary 



artery 



PERICARDIUM 

 RIGHT AURICLE /, 



RIGHT VENTRICLE 



Vena cava inferior \^ 



ICxternal jugular vein. 



Left subclavian vein 

 Left innominate vein 



Left superior intercostal vein 

 DUCTUS ARTERIOSUS 



Left pulmonary artery and 



ve in 

 LEFT AURICULAR APPENDIX 



Pulmonary artery 



LEFT VENTRICLE 



The anterior surface of tbe heart is convex, and looks upwards and i'( .r\vard.<. 

 Its lower and posterior surface, whicli rests ])art]y on the diajjhragm, is Hattened. 

 The borders wliicli (Uvide the two surfaces of tlie "heart nu-et near the ajiex; the 

 right b(jrder is tliin and rather longer tlian the left, wliilst tlie latter liorder is thick 

 and wunded. 



The auricles are divided from tlie ventricles l)y a transviT-^e groove, the 

 auriculo-ventricular, which is interrujited in front l>y the origin of the jailmoiiary 

 artery. Tlie ventricles are similarly divided from eacli otlier by tbe interventricu- 

 lar groove, Avhich runs ol)liquely on the anterior and posterior surfaces of the 

 heart, meeting below just to the right of the apex where they are continuous. 



