310 DISTRIBUTION OF THE VEINS. 



CHAPTER IX. 



OF THE PARTICULAR DISTRIBUTION OF THE VEINS. 



ANATOMISTS of great respectability have very different 

 sentiments respecting the best method of describing the veins. 

 Some of them, in order to follow the course of the circulation, 

 commence with the small veins, and proceed to the large trunks 

 which are formed by their union. Others begin with the great 

 veins that empty into the heart, and proceed from them to the 

 small ramifications of the venous system, in a direction the 

 reverse of the circulation. 



As the last method is the easiest for the student of anatomy, 

 it will be adopted here ; but it must always be kept in mind, 

 that the blood flows from the small veins into the larger, and 

 not from the latter into the former, as the mode of description 

 seems to imply. 



The great trunk of the venous system differs considerably 

 from that of the arterial with respect to its connexion with the 

 heart ; for it communicates with that organ in such a manner, 

 that, when viewed from before, it appears like two vessels ; one 

 opening into the upper, and the other into the lower part of the 

 right auricle. When viewed from behind, it appears like a 

 continued tube, three-fourths of which are deficient anteriorly ; 

 and to the margin of this deficiency the right sinus or pouch of 

 the heart is connected. 



In some preparations of the heart, where all the great vessels 

 connected with it are much distended by the injection, and the 

 pulmonary vessels are injected first, the right auricle is so much 

 pressed upon from behind, by the vessels which go to the right 

 lung, that the direction of the superior and inferior portions of 



