SECT. 162.] VESSELS OF THE LIVER. J 53 



also into their trunklets during their whole course ; and, according 

 to T/ieile, capillaries open even into the commencements of the 

 sublobular veins. In all lobules or islets, whose capsular sur- 

 faces arc directed either towards the surface of the liver, or towards 

 a large vascular trunk, the intralobular vein extends nearly to their 

 ends ; whilst in others they remain more in the middle, so that 

 they are everywhere distant about the half of the diameter of the 

 lobules from the next interlobular veins of the vense portse. 



The hepatic artery accompanies, for the most part, the portal 

 vein and bile-ducts, lies together with the latter within the capsule 

 of Glisson, and presents, in its main ramifications, exactly the 

 same conditions as the portal vein. Its terminal distribution takes 

 place upon the vessels and bile-ducts, as also on the capsule of 

 Glisson, in the fibrous and serous covering of the liver, and in the 

 hepatic lobules ; and they are, accordingly, distinguished into rami 

 vascular es, capsulares, and lobulares. 



1. Rami vasculares. — During its ramification with the portal 

 vein, the hepatic artery gives off, mostly at right angles, a number 

 of small branches, which form a plexus in the Glissonian enve- 

 loping tissue, from which there arise, in part, lobular branches 

 destined to the sides of the portal canals which do not adjoin 

 the main branches of the artery, and, in part, numerous twigs for 

 the walls of the portal vein, the larger branches of the artery 

 itself, the hepatic veins, the capsule of Glisson, and the bile-ducts. 

 This vascular expansion is especially well marked on the ducts, so 

 that after a successful injection, they appear almost as red as the 

 arteries. The vena vasculares arise from a moderately wide capil- 

 lary network present in all the above-mentioned parts and around 

 the glands of the gall-ducts. As Ferrein discovered, and as 

 Kiernan and later observers have confirmed, these veins open not 

 into the hepatic veins, but into small branches of the portal vein, 

 as they go off from larger, within the capsule of Glisson, and are, 

 therefore, to be regarded as inner or hepatic roots of the portal 

 vein. For this reason, the portal vein can, in part, be injected 

 from the hepatic artery, and vice versa ; and the vascular network 

 in question becomes filled from both sides on injecting the hepatic 

 artery and portal vein ; whilst, on the other hand, it is impossible 

 to inject it directly from the hepatic veins. 



2. Rami capsulares. — Excepting some branches running to the fossa 

 ductus venosi, ligamentum teres and suspensoriiwi, heiove the entrance 

 of the artery into the liver, all the arterial branches of the envelope 

 of the liver are terminal twigs of certain arteries distributed in the 



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