472 DISSECTION OF THE ABDOMEN. 



paticje may be said to be without a sheath, except in the larger trunks ; 

 so that when they are cut across the ends remain patent, in consequence 

 of their close connection with the liver structure. 



Hepatic duct (fig. 160, e). The duct commences in the biliary plexus 

 within the lobules. On leaving the lobules the radicles communicate by 

 the interlobular branches (/') ; and the smaller ducts soon unite into larger 

 vaginal branches (ef), which lie in the portal canals with the other vessels. 

 Lastly, the ducts are collected into a right and a left trunk (fig. 158, e), 

 and leave the liver at the transverse fissure. 1 



Structure. The moderately-sized hepatic ducts consist of a fibrous coat, 

 lined by a mucous layer with cylindrical epithelium ; and penetrating the 

 wall is a longitudinal row of openings, on each side, leading into sacs, and 

 into branched tubes which sometimes communicate. In the fine inter- 

 lobular ducts the coat is formed by a homogeneous structure, with colum- 

 nar epithelium (Henle). 



Lymphatics of the liver are superficial and deep. The superficial of 

 the upper surface join the lymphatics in the thorax by piercing the dia- 

 phragm, and end for the most part in the sternal glands ; those on the 

 under surface enter chiefly the glands by the side of the abdominal aorta, 

 a few uniting with the deep lymphatics, and the coronary of the stomach. 



The deep lymphatics accompany the vessels through the liver, and 

 communicate with one of the large contributing trunks of the thoracic 

 duct. 



Nerves come from the sympathetic and the pneumo-gastric, and ramify 

 with the vessels ; but their mode of ending is not ascertained. 



THE GALL-BLADDER. 



The gall-bladder (fig. 162) is the receptacle of the bile. It is situate 

 in a depression on the under surface of the right lobe of the liver, and to 

 the right of the square lobe. It is pear-shaped, and its larger end (fundus) 

 is directed forwards beyond the margin of the liver ; whilst the smaller 

 end (neck) is turned in the opposite direction, and bends downwards to 

 termidate in the cystic duct by a zigzag part. 



In length the gall-bladder measures three or four inches, and in breadth 

 rather more than an inch at the widest part. It holds rather more than 

 an ounce. 



By one surface it is in contact with the liver, and on the opposite it is 

 covered by peritoneum. The larger end touches the abdominal wall oppo- 

 site the tip of the cartilage of the tenth rib, where it is contiguous to the 

 transverse colon ; and the small end is in contact with the duodenum. 



Structure. The gall-bladder possesses a peritoneal, a fibrous and mus- 

 cular, and a mucous coat. 



The serous coat is stretched over the under or free surface of the gall- 

 bladder, and surrounds the large end. 



The fibrous coat is strong, and forms the framework of the sac ; inter- 

 mixed with it are some involuntary muscular fibres, the chief being lon- 

 gitudinal, but others circular. 



1 Aberrant ducts exist between the pieces of the peritoneum in the left lateral 

 ligament of the liver, and in thepons bridging over the vena portse and vena cava ; 

 they anastomose together, and are accompanied by branches of the vessels of the 

 liver, viz., vena portse, hepatic artery, and hepatic vein. 



