Heart. 



Carotitsin. 



A.subclav. 



sin. 



519. The Heart and Large Vessels. 



View from behind, l / z natural size. 



Up to the fourth month of embryonic life the position of the 

 heart is a vertical one; in the adult it is placed obliquely, the long 

 axis of the heart forming with that of the body an angle of about 50. 

 The base of the heart is situated between the second and third left 

 ribs and extends to the interspace between fourth and fifth right costal 

 cartilages ; its apex lies behind the anterior extremities of the left fifth 

 and sixth ribs. The long axis of the heart is therefore placed obliquely 

 from right to left from above downwards, and the base is further 

 posterior than the apex. 



