272 VENOUS PULSE. [BOOK i. 



passes on through them and through the capillaries, and is con- 

 tinued on into the veins. A similar venous pulse is also some- 

 times seen in other organs. 



Careful tracings of the great veins in the neighbourhood of the 

 heart shew elevations and depressions, which appear due to the 

 variations of intracardiac (auricular) pressure, and which may 

 perhaps be spoken of as constituting a " venous pulse ", though 

 they have a quite different origin from the venous pulse just 

 described in the salivary gland ; but at present they need further 

 elucidation. In cases however of insufficiency of the tricuspid 

 valves, the systole of the ventricle makes itself distinctly felt in 

 the great veins ; and a distension travelling backwards from the 

 heart becomes very visible in the veins of the neck. This is 

 sometimes spoken of as a venous pulse. 



Variations of pressure in the great veins due to the respiratory 

 movements are also sometimes spoken of as a venous pulse ; the 

 nature of these variations will be explained in treating of respi- 

 ration. 



