SEMIOLOGY OF THE ORGANS OF CIRCULATION. 



371 



Palpation is performed by placing the open hand on the cardiac zone. 

 In this way the cardiac shock can be felt, its degree of intensity judged, 

 and, in an imperfect manner, its rhythm. 



Percussion by means of the fingers or a pleximeter discloses the 

 extent of the physiological area of partial dulness, due to the presence of 

 the heart, as well as its variations in pathological conditions, particularly 

 in pericarditis with marked exudation. 



In such cases there may even be complete dulness when the distended 

 pericardium thrusts upwards the corresponding pulmonary lobe, and comes 

 in contact with the internal 

 surface of the thoracic wall, or, 

 in cases of pericardial pneu- 

 matosis, exaggerated resonance, 

 and a tympanitic sound. 



Auscultation is carried out 

 either directly or by the stetho- 

 scope or the phonendoscope. 

 The normal or pathological 

 sounds of the heart are thus 

 ascertained, as well as the in- 

 tensity of the cardiac beats and 

 sounds, the frequency of the 

 rhythm, etc. 



When injuries have oc- 

 curred which cause murmurs, 

 it is best to use the stethoscope 

 and to apply it at the points 

 where murmurs are heard at 

 their maximum intensity, i.e., 

 exactly at the spot where the car- 

 diac shock is noted, and towards 

 the base, in the region where 

 the great arterial trunks begin. 



In the latter case it is often useful to draw the left fore leg forward. 



Arteries. The arteries are rarely the seat of lesions that can be 

 detected by examination, and therefore such examination is usually 

 limited to noting the state of the pulse. 



Arteritis and thrombosis of arteries are rare, and although lesions 

 of atheroma have been discovered in certain chronic diseases, such as 

 tuberculosis, chronic diarrhoea, etc., they are difficult to detect, even 

 on examination per rectum of the bifurcation of the aorta. 



Pulse. The examination of the pulse, on the contrary, is of great 

 importance. In animals of the bovine species the pulse may be taken at 



B B 2 



Fig. 173. — Schema of a section through the 

 chest opposite the heart. P^, Left lung ; 

 Vd, right lung; cp, right and left pleural 

 cavities ; P, pericardium ; I, V-, cardiac lobes 

 of the lung interposed between the peri- 

 cardium and thoracic wall. 



