POLYSPHYGMOGRAMS. 95 



and measure its distance from the beginning of the upstroke. 

 Several measurements should be taken from each member of the 

 group. How can the length of the pulse wave be calculated? 



In the more or less arbitrary lettering of the waves observed in 

 pulse tracings, the main upstroke is marked 3, in the case of the 

 carotid and 4 in that of the radial ; the dicrotic notch of the carotid 

 is 5 and of the radial 6. The distances between 3 and 5 and be- 

 tween 4 and 6 represent respectively the time during which the 

 heart is pumping blood into the arteries, i.e., the semilunar valves 

 are open. It is called the sphygmic period ui period E. 



B. The Venous or Jugular Pulse Curve. Have the observed 

 person lie down with his head slightly raised by a cushion and bent 

 to the right side. Place the receiver (thistl" funnel) over the jugular 

 bulb on the right side of the neck. This lies immediately above 

 the inner end of the clavicle. Bring the point of the lever of the 

 recording tambour to write with a minimal amount of friction on 

 a drum. Since a venous pulse tracing cannot be interpreted with- 

 out a simultaneous tracing from an artery, adjust the button of a 

 receiving tambour over the radial artery and arrange the writing 

 style of its recording tambour so as to write on the drum in the 

 same perpendicular as the style of the venous tambour. If no 

 satisfactory tracing can be secured from the radial, try the carotid. 

 Remember to inscribe alignment marks at short intervals. While 

 the tracing is being taken it is usually advisable that the respiratory 

 movements be suspended. 



To INTERPRET THE VENOUS CURVE. Make a vertical mark 

 on the arterial pulse tracing corresponding to the beginning of 

 the pulse upstroke. If this is done on the radial pulse tracing, 

 measure 1/10 sec. in front of it and make another vertical mark. 

 (This mark is to allow for the time lost in propagation of pulse from 

 heart to radial. It is determined according to Exp. A). 



This line 3 corresponds to the beginning of the sphygmic period 

 of ventricular systole, i.e., to the opening of the semilunar valves. 

 Measure the distance from line 3 to the nearest alignment mark. 

 By measuring off the same distance from the corresponding align- 

 ment mark of the venous tracing line 3 will be found to fall at the 

 beginning of a small wave which is marked c. The small wave in 

 front of c is marked a and is due to auricular systole. The large 



