534 CIRCULATION OF BLOOD AND LYMPH. 



pour into the auricle during the whole period of the systole of the 

 ventricle and of the closure of the auriculo ventricular valves. 

 In this way the wave v is produced. It is frequently of irregular 

 or toothed form and rises somewhat gradually to its maximum. 

 The end or maximum of the wave falls in with the beginning 

 of the muscular relaxation of the ventricle, and the return, there- 

 fore, of the base of the ventricle to its diastolic position. Im- 

 mediately afterward the auriculoventricular valves open, and the 

 blood accumulated in the auricles is discharged into the ventricle, 



Fig. 218. Simultaneous tracings of the jugular pulse, the carotid pulse, and the 

 apex beat. (Bachmann.) At the bottom of the tracing the time is given in fiftieths of 

 a second. The vertical lines 0, 1, 2, 3, etc., mark synchronous points on the curves. 

 A, The auricular wave; s, the so-called c wave caused by the systole of the ventricle; v, the 

 stagnation wave caused by the filling of the auricle. It will be noticed that the c wave 

 (marked s in the tracing) occurs at the beginning of the ventricular systole as marked on 

 the apex beat, and shortly before the pulse in the carotid artery. The height of the v wave 

 is reached just after the occurrence of the dicrotic notch on the carotid wave, and coin- 

 cides with the opening of the auriculoventricular valves; Af, the negative wave caused by 

 the effect of the ventricular systole; Vf, the negative wave following the opening of the 

 auriculoventricular valves. 



causing again a sudden fall of pressure in the auricles and veins, the 

 third negative wave. 



One view of the relation of the different venous waves to the 

 sequence of events in the ventricle and aorta is shown in the 

 diagram given by Fredericq, which is reproduced in Fig. 219. 

 Following this author,* the series of positive and negative waves 

 which may usually be shown in the auricles and great veins during 

 a single heart beat may be enumerated as follows : 



1. The auricular wave (a wave), auricular systole. 



* Fredericq, " Centralblatt f. Physiol.," 22, No. 10, 1908. 



