i86 



THE VENOUS PULSE. THE PHLEBOGRAM. 



If it be considered that the distended jugular vein, in which the blood is 

 subject only to slight pressure, communicates directly with the auricle, it will be 

 readily understood that a contraction of the auricle will be propagated peripherally 

 into the jugular vein as a positive wave. In Fig. 72, 9 and 10 represent the 

 venous pulse from healthy individuals : the section a b corresponds to the auricular 

 contraction. Landois has occasionally seen this composed of two slight elevations, 

 corresponding to the contraction of the auricular appendage and the auricle. As 

 the blood of the right auricle is subsequently thrown into agitation by the sudden 

 tension of the tricuspid valve, the closure of the latter, which is synchronous with 

 the systole of the right ventricle, sends a positive wave into the jugular vein, 

 and this appears in 9 and 10 as the section b c. Finally, the sudden closure of 

 the pulmonary valves may even be propagated through the blood in the ventricle 

 as far as the auricle and still further up in the jugular vein, and be registered by 

 the production of a small positive wave (e) . As the aorta is in immediate contact 

 with the pulmonary artery, a delicate wave may, on sudden closure of the aortic 

 valves (in 9 at d), be generated at this point in a similar manner. During the 



FIG. 72. Various Forms of Venous Pulse, Chiefly after Friedreich: 1-8, with tricuspid insufficiency; 9 and 10, 

 venous pulse from the jugular vein of a healthy individual. In all of the curves a b indicate contraction of 

 the right auricle; b c, that of the right ventricle; d, closure of the aortic valves; e, closure of the pulmonary 

 valves; e f, diastole of the right auricle. 



diastole of the auricle and of the ventricle blood flows freely toward the heart, 

 and in consequence the vein collapses and the writing-lever makes a down-stroke. 



According to Knoll the normal jugular pulse is due partly to the positive wave 

 caused by the contraction of the right auricle and partly to the negative wave 

 caused by the dilatation of the ventricle ; while, the increase in the venous pressure 

 that takes place between these two phases is brought about by interference with 

 the flow of venous blood to the heart during the auricular pause. 



In the sinuses of the skull the blood likewise exhibits pulsatory movement, 

 because blood flows freely into the heart during diastolic relaxation. Under 

 favorable conditions this pulsatory movement may be propagated as far as the 

 veins of the retina and thus give rise to the retinal venous pulse, which was familiar 

 to the earlier investigators. 



Pathological. The venous pulse may be much larger and much more pro- 

 nounced in all its characteristic parts in cases of tricuspid insufficiency. A mo- 

 ment's reflection will show that under such circumstances every contraction of 

 the right ventricle must cause regurgitation of a certain quantity of blood into 



