620 



TEE VEINS. 



opinion ; and there is every reason to believe ttat 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 

 Fig- 29i. intermediate to the subhepatic and 



suprahepatic vessels. If any other 

 means of communication exist, they 

 must be extremely small. 



Constituent vessels of the verm portcB. 

 — 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-epiploie veins and 

 anterior gastric. 



We will make a rapid survey of 

 all these vessels. 



1. Boots of the Vena Portoe. 

 A. Great Mesenteric oe An- 

 terior Mesaeaio 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, cseoum, 

 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 poBT^ AND ITS ROOTS ; PARTLY by the Suprasternal and diaphragmatic 



THEOEETioAL. curvatuTes, beyond which it divides 



1, Trunk of the vena portse; 2, Its origin; j^^^ ^^^ satellite branches for the 



3, Veins of the small intestine; 4, Ilio- ■,. , . v- t, i. „„ ;„ 



' •""°.'" Tr^t„,.„„i „„„,! „J„ . fi Tn colic arteries, which anastomose in 



c^cal vein ; 5, External cajcal vein ; b, in- -i i i • 



ternal caecal vein ; 7, Great mesaraic veia ; arcade towards the pelviC Curvature, 



8, 9, Colic veins forming the roots of that like the arteries they accompany. 



vessel ; 10, Collateral vein sometimes con- j(. jg therefore by the union of twO 



tinuing the left colic, and joining the great ^. . ^j,j 294, 8, 9) that the 



mesaraic vein near its origin; 11, Lom- v. & . . i » /•. , t j 



men confluent of the small mesaraic and great mesaraic vem IS constituted, and 



splenic veins ; 12, Small mesaraic vein and in whose formation numerous collateral 



affluents concur ; among these may be 

 noticed the two cwcal veins (Fig. 294, 

 5, 6), the ilio-ccecal vein (Fig. 294, 4) 

 coming from the origin of the floating 

 ing colon ; g, Rectum ; h, Portion of the colon, and the veins of the small intes- 



great omentum; i. Spleen ; i. Mesentery ; ^ .^^^ . ^^gg^^g arranged SO exactly like 

 A, Colic mesentery. ^ , , . ^ ■ ±i j_ 



the corresponding arteries that we may 

 dispense with any further description of them. 



its collateral branches ; 13, Splenic vein ; 

 14, Left gastro-epiploie vein; 15, Eight 

 ditto ; 16, Posterior gastric vein. — -a, 

 Stomach ; b, Duodenum ; c. Small intes- 

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



