DISEASES OF THE CIRCULATORY APPARATUS. 



EXAMINATION OF THE CIRCULATORY APPARATUS. 



Examination of the Heart. 



Anatomy of the Heart. — The normal position of the heart may 

 be seen in Fig. GG. It lies on the left side, but not so far as is seen in 

 other domestic animals. The direction of its axis is not vertical, l)ut 

 extends slightly in a posterior direction, with a slight curve toward the 

 left side. The base of the heart extends from the third to the seventh 

 rib; the apex extends backward toward the diaphragm. Superiorly the 

 heart lies close to the large vessels — the trachea and the oesoi3hagus — 

 and close on all sides to the lobes of the lungs. In its inferior portion it 

 lies close to the chest-wall, extending from the third to the seventh ril). 

 In the heart-sections we find the following arrangement: the right 

 section lies in a right anterior direction from its axis and the left lies 

 in a left posterior direction. 



Fig. 66.— The heart in position: a. Right ventricle; b, left ventricle; c, left .auricle; d, right auricle;/, 

 pulmonary artery; g, aorta; k, cesophagus; /, diaphragm. 



The size of the heart varies greatly in different animals, even when 

 in a normal condition, and it is, therefore, impossible to lay down any 

 relative rule as to its size or dimensions. According to Colan, the weight 

 of the heart compared with that of the body is 1 to 90; and according to 



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