1706 



HUMAN ANATOMY. 



while its duct and glandular elements are derived from a sprout from the duodenum ; 

 hence the liver, as are other glands connected with the digestive tract, is an out- 

 growth and appendage of the alimentary tube. Its peculiar shape is chiefly due to 

 the pressure of surrounding organs, as its tissue is so plastic that it is moulded by 

 them. In the adult it becomes firmer from the increase of connective tissue, but 

 under normal circumstances it is always very soft, and, unless hardening agents are 

 used before its removal, collapses into a flattened cake-like mass affording little 

 information as to its true form. Indeed, it is only in the present generation, since 

 the introduction of adequate methods of hardening hi situ, that this has been 

 learned. The liver in general may be described as an ovoid mass which in the young 

 foetus nearly tills the abdomen, but in the adult has the appearance of having had at 

 least a third of its substance scooped out from below, the back having been left intact 

 at the right end only. The organ is therefore a thick mass in the right hypochon- 

 drium, growing thinner to the left. The greatest diameter is transverse and the 

 next vertical. The liver is usually described as composed of five lobes, — namely, 

 the right, the left, the lobe of Spigelius, the quadrate, and the caudate. More 

 properly it consists of a right and a left lobe, separated on the superior surface by 

 the falciform ligament. The other lobes are subdivisions of the right lobe, the lobe 



Fig. 1440. 



Vena cava 



Union of right, 

 and left layers 

 of falciform 

 ligament 



Right lobe. 



f^' 



Left layer of falciform 



ligament continuous 



.,-with lateral ligament 



Cardiac 

 impression 



— Left lobe 



Obliterated umbilical vein in free margin of falciform 

 ligament 



Gall-bladder 



Antero-superior surface of liver hardened in situ. 



of Spigelius being at the back and the other two below. They are described with 

 the respective surfaces. The size varies greatly with the size of the body and from 

 many other causes. The transverse diameter usually nearly equals that of the cavity' 

 of the abdomen, although it often falls an inch or so short of it. It may be given at 

 from 22-24 cm. (81^-9^ in.). The greatest vertical dimension or depth is about 

 i6cm. (6^ in.); the antero-posterior diameter 12-18. 5 cm. (4^-7^ in.). One 

 peculiar form of liver occasionally met with shows great increase of the right lobe, 

 particularly in the vertical direction, with a want of development of the left lobe, 

 which is thin and short (Fig. 1456). The weight is, with considerable variations, 

 generally from 1450-1750 gm., or approximately from 3-3^ lbs., and in the adult 

 is about one-fortieth of the body weight. The specific gravity is given at from 

 1005-1006. The color is a reddish brown. The naked eye can recognize that the 

 surface is covered with the outlines of polygons from 1-2 mm. in diameter. These 

 are the lobules, each of which is surrounded by vessels and ducts in connective tissue, 

 and contains in the middle a vessel, the beginning of the system of the hepatic vein. 

 Sometimes the centre of the lobule is lighter than the periphery, sometimes the 

 reverse, depending upon whether the blood has stagnated in the portalior hepatic 

 system respectively. 



