THE LIVER. 171 i 



points along its course in the groove on the posterior surface of the liver, several 

 coming from the Spigelian lobe. Sometimes quite a large branch from the right 

 lobe opens at a low level. There is no such thing as an hepatic vein in the adult 

 considered as an isolated structure. The ramifications of the portal and hepatic 

 veins are inextricably mingled throughout, but in the main the branches of the latter 

 lie above those of the former (Fig. 1443). 



The hepatic artery, the nutritive vessel of the liver, divides into two 

 branches which, together with the bile-duct, accompany the portal vein, the two arte- 

 ries generally being on the same side of the vein. The hepatic artery gives off so 

 many branches in its course as to be almost or quite of capillary size when it reaches 

 the twigs of the portal vein that break up into the interlobular net-work. The blood 

 conveyed by the hepatic artery is distributed by three sets of branches, the capsular, 

 the vascular, and the lobular. The first ramify within the connective-tissue envelope 

 of the organ and anastomose with branches from the internal mammary, phrenic, cystic, 

 suprarenal, and sometimes right renal. The second supply the structures between 

 the lobules, especially the walls of the ramifications of the portal vein and the bile- 

 ducts. The third are small in size, and accompany the intralobular branches of the 

 portal vein for a short distance within the lobule. There is no special system of 

 veins to return the blood carried by the hepatic artery to the venous trunks outside 

 the organ, the minute veins collecting the blood from the capsular and vascular sets 

 being tributaries usually of the smaller branches of the portal vein. The blood 

 passing through the lobular arterioles is emptied into the intralobular capillary net- 

 work. 



The lymphatics of the liver constitute a superficial and a deep set, the former 

 lying beneath the peritoneum, the latter within the deeper interlobular connective 

 tissue. The superficial lymphatics of the superior surface are arranged as three 

 groups, posterior, anterior, and superior. The posterior group forms a right trunk 

 which passes from the right triangular ligament across the right crus of the dia- 

 phragm to the coeliac lymph-nodes. Middle trunks — from five to seven in number — 

 accompany the inferior vena cava to end in diaphragmatic nodes around the vein. 

 Left trunks traverse the left triangular ligament and terminate in the oesophageal 

 nodes surrounding the lower end of the gullet. The anterior group passes in the op- 

 posite direction to those just described and, crossing the anterior border of the liver, 

 empties into the hepatic lymph-nodes within the lesser omentum. The superior 

 group, the most important of those of the upper surface, ascends within the falciform 

 ligament. A number of anastomosing vessels form a posterior trunk which crosses 

 the inferior vena cava and enters the thorax with the latter, to end in the lymph-nodes 

 around the vena cava. An anterior trunk accompanies the round ligament to the infe- 

 rior surface and ends in the hepatic nodes at the hilum. Numerous middle trunks 

 form vessels which pierce the diaphragm, to end in the anterior mediastinal nodes, 

 becoming tributaries to the right lymphatic duct. The superficial lymphatics of the 

 inferior surface include, on the right lobe, a posterior group, accompanying the vena 

 cava into the thoracic cavity, to end in nodes around that vein, a middle group passing 

 to the hepatic nodes around the cystic duct, and an anterior group terminating in the 

 same nodes as the preceding. On the left lobe the vessels pass to the nodes of the 

 hilum and about the hepatic artery. The lymphatics of the Spigelian lobe pass partly 

 to the hilum nodes and partly to those surrounding the thoracic segment of the infe- 

 rior vena cava. Communications exist between the superficial and deep lymphatics. 



The deep lymphatics include two distinct groups, the one following the branches 

 of the portal vein, the other accompanying the hepatic veins. The first descends 

 within the capsule of Glisson in company with the portal vein and other interlobular 

 vessels. On emerging at the hilum, the fifteen to eighteen trunks, arranged as 

 two groups at the ends of the transverse fissure, join the hepatic nodes. The 

 lymphatics which accompany the hepatic veins form a plexus surrounding the 

 blood-vessels and proceed towards the vena cava, with which they pass through 

 the diaphragm to enter the nodes lying immediately above the caval opening. 



The nerves are chiefly derived from the solar plexus of the sympathetic with 

 some fibres from the left pneumogastric which reach the liver by passing from the 

 anterior surface of the stomach between the layers of the lesser omentum. The 



