THE CIRCULATION OF THE BLOOD 369 



problems of the heart, both physiologic and pathologic, to record the 

 carotid pulse and the cardiac impulse simultaneously. 



The Venous Pulse. By this term is meant a pulsation of the large veins 

 in the neighborhood of the heart but more especially in the jugular veins. 

 It is caused by variations of pressure transmitted backward into the veins 

 during and after the systole of the auricle. Though the venous pulsation is 

 not very marked in physiologic conditions it frequently becomes pronounced 

 in certain pathologic conditions of the heart. 



The pressure variations in the jugular vein can be recorded by applying 

 over the vein a properly constructed tambour, a glass funnel or a Mackenzie 

 metal tambour connected with a suitable recording tambour. A graphic 

 record of a normal venous pulse thus obtained, shown in Fig. 174, is rather 

 complicated, consisting of three positive and three negative waves which 

 are related to variations of pressure in the right auricle, the result of the 

 successive contractions of the auricular and ventricular walls and the action 

 of intra-ventricular structures. 



FIG I7 4 .-SIMULTANEOUS TRACINGS OF THE JUGULAR PULSE, THE CAROTID PULSE 'AND THE 



APEX ^.-(Bachmann.} At the bottom of the tracing the time is given in the fiftieths of a 

 fprnnrf The vertical lines o I, a, 3, etc., mark synchronous points on the curves. A t T 

 auricular ^"h! fso-called' ^ave'caused by the systole ofthe ventricle; t, the stagnation wave 



following the opening of the auriculo-ventricular valves. 



As the venous pulse is a very evident symptom in some pathologic condi- 

 tions of the heart, and as its proper interpretation assists m th< : diagnos 

 these conditions, it has become of much significance m moderr chmca medi 

 cine For purposes of interpretation it is desirable to obtain si 

 graphic rec P ord^ not only of the venous pulse, but of the carotid or radial 

 pulse, and of the cardiac impulse as well. In the accompanying 

 these three records are represented. 



The generally accepted interpretation of these waves is as follows. 



4 



