////: r<:n:i;i'H: r/:.v.i CAVA. en 



AKTICLK III. POSTERIOR VENA OAVA. (Figs. 258, v; 259, /; 293.) 



This vein, whoso volume is not equalled by that of nny other vessel iu 

 the body, commences at the eutranco to the pelvis by two largo roots, thu 

 ylci-crnral trunk*. 



Fnnii this point it is directed forward, beneath tho bodies of the lumbar 

 vertebra), soon reaches tho superior border of tho liver, where it leaves tho 

 lumbar region to lodge itself in the fissure excavated on tho anterior face 

 of that gland ; passing through this, it traverses the aponeurotic centre of 

 tin; diaphragm, and opens into tho postero-external part of tho right auricle 

 of tho heart. 



In this cpurse, the posterior vena cava is naturally divided into three 

 portions a sulhiHtbar, hepatic, and thr(n-i<\ 



The sublumbar portion, placed to the right of the abdominal aorta and to 

 the left of the right kidney and suprarenal capsule, is maintained against 

 the common inferior vertebral ligament and the left small psoas muscle by 

 tin peritoneum and the pancreas. It responds, besides, to the right renal 

 artery, which crosses its face perpendicularly, as well as the corresponding 

 _'n-:it splanchnic nerve and the nervous divisions of tho right renal and 

 lumbo-aortie plexuses. 



In its hepatic portion, the posterior vena cava is only related to the liver 

 and diaphragm, which form a complete canal around it. 



Tho thoracic portion is lodged between the right lung and its internal 

 accessory lobule, and enveloped by a particular serous fold a dependency 

 from the right pleura, and which has been already described (page 465). 



Collateral afferents. Those vessels which, as considerable as they are 

 numerous, open into the posterior vena cava, are, enumerating them from 

 before to behind : 



1. The diaphragmatic veins. 



2. The vena portce, a trunk into which are collected tho majority of tho 

 visceral abdominal veins, and which, instead of opening directly into tho 

 vena cava, is divided in tho liver like an artery, reconstituting itself 

 into a certain number of thick branches the supraJiepatic vessel*, which 

 enter the vena cava on its way through tho anterior fissure of tho liver. 



3. Renal veins. 



4. Spermatic veins. 



5. Lumbar veins. 



All these vessels will be studied, in the order above indicated, before tho 

 roots or pelvi-cmral trunks of tho vena cava. 



1>I.\ I'M K\i; MAT 1C Vi 



These are two, sometimes time, enormous vessels lodged in the texture of 

 the aponeurotic centre, commencing by several branches in the fleshy portion 

 of the muscle, and entering tho vena cava at tho moment when it traverses 

 the diaphragm. 



VENA POBTJS. (Figs. 293 ; 294.) 



Tho manner in which this vessel comports itself gives it an altogether 

 Peculiar physiognomy, and has caused it to bo c i as a separate, 



vascular system. After what has been already said concerning the structure 

 of tho liver, it cannot bo ignored that the vena port is distributed in 

 that gland exactly like an artery. 



