166 



NORMAL ANATOMY OF THE LIVER. 



an irregularly pentagonal or hexagonal outline 

 with sharp or rounded angles in proportion to 

 the smaller or greater quantity of Glisson's 

 capsule contained within the liver. Each 

 lobule is divided upon its exterior into a 

 base and a capsular surface. The base 

 (Jig. 34, 4) corresponds with one extremity 

 of the lobule, is flattened and rests upon an 

 hepatic vein, which is thence named sub-tabular. 

 The capsular surface (fig. 34, 3, 3) includes 

 the rest of the periphery of the lobule, and has 

 received its designation from being inclosed in 

 a cellular capsule derived from the capsule of 

 Glisson. In the centre of each lobule is a 

 small vein, the intra-lobular (Jig. 34, 5, 6, 

 Jig. 35, 3_) which is formed by the conver- 

 gence of six or eight minute venules from the 

 rounded processes situated upon the surface of 

 the lobule. The intra-lobular vein thus con- 

 stituted takes its course through the centre of 

 the longitudinal axis of the lobule, pierces the 

 middle of its base, and opens into the sub-lo- 

 bular vein. The circumference of the lobule 

 with the exception of its base, which is always 

 closely attached to a sub-lobular vein, is con- 

 nected by means of its cellular capsule with the 

 capsular surfaces of surrounding lobules. The 

 cellular interval between the lobules is the in- 

 terlobular fissure (Jig. 34, 8, fig. 35, 2), and 

 the angular interstices formed by the appo- 

 sition of several lobules are the interlobular 

 spaces (Jig. 34, 9, fig. 35, 1). 



Fig. 35. 



Angular lobules in a state ofaneBtnia. From Kiernan's 



paper. 



No. 1, interlobular spaces, containing the larger 

 interlobular branches of the portal vein, hepatic 

 artery and duct ; 2, interlobular fissures ; 3, intra- 

 lobular veins formed by minute venules which con- 

 verge towards the centre of the lobules. 



The lobules present considerable variety of 

 form dependent upon their situation and upon 

 the manner in which they are examined. For 

 instance, the section of a lobule divided trans- 

 versely has an irregularly pentagonal or hexa- 

 gonal figure, and longitudinally a foliated ap- 

 pearance. The lobules of the centre of the 

 liver are angular and smaller than those of the 

 surface, on account of the pressure to which, 

 from their position, they are submitted by sur- 

 rounding lobules. They are also more an- 

 gular in some animals than in man. The sur- 

 face of the liver of the cat, in which the portal 

 vein is injected, has a beautiful reticulated ap- 

 pearance produced by angular meshes of an 

 hexagonal figure; the hexagonal outline being 



formed by the interlobular fissures, reddened by 

 the injection in the minute branches of the 

 portal vein, and the included area by the lo- 

 bule viewed upon its transverse diameter. In 

 a section of the liver made from the free margin 

 to the posterior border in the direction of the 

 hepatic veins, the lobules are found to be 

 larger than in a section made transversely to 

 those vessels. The lobules of the exterior, par- 

 ticularly on the concave side aud posterior 

 border, are for the same reason larger from 

 lying obliquely to the surface and correspond- 

 ing in direction with the course of the sub- 

 lobular veins. They are also more rounded 

 from the absence of compression by surround- 

 ing lobules. But one appearance described by 

 Kiernan is peculiarly characteristic of the lo- 

 bules which form the surface of the liver, the 

 superficial lobules. The word surface in this 

 instance does not refer simply to the periphery 

 of the organ, but also to the various canals 

 channelled through its interior for the passage 

 of the portal vein, hepatic ducts, and hepatic 

 artery, and also for the main trunks of the he- 

 patic vein, " all these canals being" as it were 

 " tubular inflections inwards of the super- 

 ficies of the liver." The superficial lobules 

 (Jig. 34, 2, Jig. 35) are not terminated by 

 a rounded extremity like those of the centre, 

 but are flat and apparently incomplete, and as 

 though cut across by a transverse incision. This 

 peculiar form gives to the anatomist a natural 

 surface which affords all the advantages for ob- 

 servation of a transverse section, and enables 

 him to detect by external examination the rela- 

 tive condition of both the central portion and 

 surface of the lobule. In these lobules also 

 the intra-lobular hepatic vein, instead of being 

 entirely concealed within the lobule, commences 

 directly from the flat surface. A knowledge of 

 this structure, says Kiernan, " enables us in in- 

 jecting the hepatic veins to limit the injection 

 to this system of vessels, which is effected by 

 withdrawing the syringe when the injection ap- 

 pears in minute points upon the surface of the 

 liver." Occasionally double lobules, or lobules 

 having two intra-lobular veins, are seen upon 

 the surface. 



" Each lobule," according to Kiernan, " is 

 composed of a plexus of biliary ducts, of a 

 venous plexus formed by branches of the portal 

 vein, of a branch (intra-lobular) of an hepatic 

 vein, and of minute arteries; nerves and absorb- 

 ents, it is to be presumed, also enter into their 

 formation, but cannot be traced into them." 

 " Examined with the microscope, a lobule is 

 apparently composed of numerous minute 

 bodies of a yellowish colour, and of various 

 forms, connected with each other by vessels. 

 These minute bodies are the acini of Malpighi." 

 " If an uninjected lobule be examined and 

 contrasted with an injected lobule, it will be 

 found that the acini of Malpighi in the former 

 are identical with the injected lobular plexus of 

 the latter, and the bloodvessels in both will be 

 easily distinguished from the ducts." 



GLISSON'S CAPSULE is the web of cellular 

 tissue which envelopes the hepatic artery, portal 

 vein, and ductus communis choledochus during 

 their passage through the right border of the lesser 



