THE HEART. 



139 



13. The Heart (Fig. 37) resembles a pear in form, and 

 is placed in a slanting position inside the chest, with its 

 smaller end downwards. It lies just above the diaphragm 

 (Fig. 2), and behind the lower two-thirds of the breast- 

 bone. Its upper end, or base (so called because it is the 



FIG. 37. The heart and the arteries and veins opening into it, seen from the 

 front. The pulmonary artery has been cut short close to its beginning, i, right 

 ventricle; 2. left ventricle; 3, root of the pulmonary artery; 4, 4', 4", the aorta; 5, 

 part of the right auricle; 6, part of the left auricle; 7, 7', innominate veins joining 

 the upper vena cava; 8, inferior vena cava; 9, one of the veins from the liver, join- 

 ing the inferior vena cava. 



larger end, although the upper), projects a little to the 

 right of that bone, and its lower end, or apex, a little 

 to the left, where it may easily be felt beating by pressing 

 with the finger between the cartilages (p. 18) of the 



13. Shape and position of the heart ? Where does its base project ? 

 Where may its apex be felt beating ? Its size ? 



