THE GALL-BLADDEK AND BILE-PASSAGES. 1201 



vessels which mostly pass to the inferior part of the inferior vena cava. The hepatic 

 veins and their branches are not accompanied by branches of the bile-ducts, and are 

 surrounded by a very small amount of connective tissue. 



The lymph vessels of the liver are arranged in a superficial and a deep set : 1. The superficial 

 set lies beneath the peritoneum on both (a) the visceral and (&) the parietal surfaces of the organ. 

 (a) The vessels from the visceral surface pass chiefly to the hepatic glands, which lie between the 

 layers of the lesser omentum ; but some of them, from the posterior surface on the right lobe, 

 join the lumbar glands, and others, from the posterior surface on the left lobe, go to the cceliac glands. 

 (&) The vessels from the inferior surface pass in various directions. Those from the adjacent 

 parts of the right and left lobes pass up in the falciform ligament, and pierce the diaphragm to 

 reach the anterior mediastinal glands, and end finally in the right lymphatic duct. Those from 

 the anterior part of this surface pass down to the inferior aspect, and join the hepatic glands 

 in the lesser omentum. The lymph vessels from the back of the right lobe pierce the diaphragm 

 between the layers of the coronary ligament, and join some glands in the thorax around the upper 

 end of the inferior cava ; others run in the right triangular ligament, and either pierce the 

 diaphragm and end in the anterior mediastinal glands, or, turning down, join the coeliac group, 



2. The deep lymph vessels accompany either (a) the portal or (6) the hepatic veins, (a) The 

 former set pass out through the porta hepatis and join the hepatic glands, the efferent vessels of 

 which join the cceliac glands. (6) Those which accompany the hepatic veins pierce the diaphragm 

 with the vena cava, and having formed connexions with the group of glands at its superior end, 

 within the thorax, turn down and join the beginning of the thoracic duct. 



The nerves, which are chiefly of the non-medullated variety, are derived from the left 

 vagus and the cceliac plexus of the sympathetic. The branches of the former pass from 

 the front of the stomach up between the layers of the lesser omentum to the liver. Those of 

 the latter pass from the cceliac plexus along the hepatic artery forming the hepatic plexus to 

 the porta hepatis, where they enter the liver with the blood-vessels. They are distributed chiefly 

 to the walls of the vessels and of the bile -ducts. 



THE GALL-BLADDER AND BILE-PASSAGES. 



Under this heading we have to consider the hepatic ducts, the gall-bladder, the 

 cystic duct, and the bile-duct. 



The excretory ducts of the liver (Fig. 943) begin within the hepatic cells as minute 

 channels. Thence they run between the hepatic cells (Fig. 943), and are known as the 

 ductus biliferi. 



Outside the lobules these join (Fig. 943) the ductus interlobulares which, by 

 uniting, form larger and larger ducts, and finally end in two, or more, chief branches, 

 a larger from the right, and a smaller from the left lobe, which unite immediately 

 after leaving the liver to form the ductus hepaticus. 



As a rule, five or six ducts leave the liver at the porta hepatis ; they generally unite into 

 right and left main ducts ; sometimes they all converge towards, and unite at the beginning 

 of the hepatic duct. It is interesting to note that the ducts from the caudate lobes and process, 

 join the left branch of the main duct. 



Ductus Hepaticus. The hepatic duct is formed within the porta hepatis by 

 the union of right and left chief ducts (Fig. 944), and passes downwards, with an 

 irregular course, and, just beyond the porta hepatis, is joined by the cystic duct 

 (Fig. 944) to form the ductus choledochus or bile-duct (O.T. common bile-duct). 

 In length the hepatic duct usually measures about 1 to 1J inch (25 to 31 mm.), 

 and in breadth, when flattened out, nearly J inch (6 mm.), or about as much as a 

 goose quill. It lies, practically altogether, within the porta hepatis. 



Vesica Fellea (Gall-bladder). The gall-bladder, with the cystic duct, may be 

 looked upon as a diverticulum of the bile-duct, enlarged at its extremity to form a 

 reservoir for the bile. It is pear-shaped, and lies obliquely on the inferior surface of 

 the liver (Fig. 944). The wide end, or fundus, usually reaches the anterior border of 

 the liver where there is sometimes a notch to receive it and comes in contact with 

 the anterior abdominal wall (Fig. 944). The corpus (body) runs backwards, upwards, 

 and to the left, lying in the fossa for the gall-bladder, and near the porta hepatis passes 

 rather abruptly into the narrow neck. The collum (neck) is curved medially towards 

 the porta hepatis, in the form of the italic letter s, and when distended it presents 

 on its surface a spiral constriction which is continued into the beginning of the 

 cystic duct, and is due to a series of crescentic folds placed somewhat spirally 

 round the interior of its cavity, forming the valvula spiralis (Heisteri). Having 

 arrived near the porta hepatis, much reduced in size, it passes into the cystic duct. 



As a rule the gall-bladder is covered by the peritoneum of the inferior surface 



77 



