620 



THE VEINS. 



opinion ; and there is every reason to believe that the system of the vena port 

 and that of the vena cava do not communicate, in the adult, otherwise than 

 . by the capillary network which is 



intermediate to the subhepatic and 

 suprahepatic vessels. If any other 

 means of communication exist, they 

 must be extremely small. 



Constituent vessels of the vena portce. 

 The three roots of this vein are the 

 great and small mesenteries and the 

 splenic vein. , 



The collateral affluents it re- 

 ceives on its course are principally 

 two : the right gastro-epiploic veins and 

 anterior gastric. 



We will make a rapid survey of 

 all these vessels. 



1. Hoots of the Vena Portce. 



A. GREAT MESENTERIC OR AN- 

 TERIOR MESARAIC VEIN (Fig. 293, 

 44 ; 294, 2, 7). This is an enormous 

 venous canal into which flows the 

 blood that has passed through the 

 walls of the small intestine, ca3cum, 

 large colon, and the origin of the small 

 colon, and whose divisions correspond 

 exactly to the different branches fur- 

 nished by the great mesenteric 

 artery. 



When traced from its opening to 

 its origin, in an inverse direction to 

 the course of the blood, it is observed 

 to lie between the two colic arteries, 

 and proceed beyond the fold formed 



THE VENA PORT^ AND ITS ROOTS ; PARTLY by the suprasternal and diaphragmatic 

 THEORETICAL. curvatures, beyond which it divides 



1, Trunk of the vena portse ; 2, Its origin ; into two sa t e llite branches for t'he 



ternal csecal vein ; 7, Great mesaraic vein ; 

 8, 9, Colic veins forming the roots of that 

 vessel ; 10, Collateral vein sometimes con- 

 tinuing the left colic and joining the great 

 mesaraic vein near its origin; 11, Com- 

 mon confluent of the small mesaraic and 

 splenic veins ; 12, Small mesaraic vein and 

 its Collateral branches ; 13, Splenic vein ; 

 14, Left gastro-epiploic vein; 15, Right 

 ditto; 16, Posterior gastric vein. a, 

 Stomach; 6, Duodenum* c, Small intes- 

 tine ; d, Caecum ; e, Large colon ; /, Float- 

 ing colon ; g, Rectum ; A, Portion of the 

 great omentum ; t. Spleen ; j, Mesentery ; 



k > C( 

 dispense with any further description 



arcade towards the pelvic curvature, 

 like the arteries they accompany. 



j j g therefore by the union of two 

 fo . . ^ ^ g ^ ^ ^ Q 

 " x. o . . / 



great mesaraic vein is constituted, and 

 in whose formation numerous collateral 

 affluents concur ; among these may be 



{ ^ the twO CtecaZ veins (Fig. '294, 



. _> Q , A \ 



5, 6), the lllO-CCBCal vein (Fig. 294, 4) 



coming from the origin of the floating 

 colon, and the veins of the small intes- 

 ^ . vesge i s arranged SO exactly like 

 the corresponding arteries that we may 

 of them. 



