XL] THE ALIMENTARY SYSTEM. 451 



It is placed rather to the right side of the body, imme- 

 diately beneath the diaphragm and above the stomach, and 

 lies within the cartilages of the ribs. The aorta, vena cava, 

 and the crura of the diaphragm are interposed between it 

 and the bodies of the vertebrae, whence it extends to the front 

 of the abdominal cavity and to its right and left sides. 



It is a solid organ, of a dull reddish-brown colour, smooth 

 and convex above, concave and uneven below. It is divisible 

 into certain parts (or lobes), which are defined partly by 

 grooves and notches, partly by ligaments and blood-vessels. 



In the Tenth Lesson of the present course was described 

 how blood is conveyed to the liver from the viscera by the 

 portal vein, and from the liver to the adjacent vena cava 

 by the hepatic veins, while the nutritive blood from the 

 aorta is distributed to the liver by the hepatic artery, itself a 

 branch of the cceliac axis. It was also noted how in an early 

 stage of development a stream of blood is conveyed by a 

 temporary vessel, the umbilical vein, which in part joins the 

 vena porta, in part sends small branches into the liver, and 

 in part directly unites with the vena cava by a temporaiy 

 canal called the ductus venosus. 



Now the liver, when viewed above, is seen to be divisible 

 into two unequal parts, one right and the other left, by means 

 of a membranous ligament (called the broad or falciform 

 ligament} which descends to it from the adjacent surface of 

 the diaphragm and consists of two folds of peritoneum, as 

 will be hereafter explained. This ligament is attached to the 

 liver in a line running from the posterior margin of that organ 

 to its anterior one, and the part of the liver on the left of 

 the ligament is much smaller than that on its right. 



Viewing the liver on its under surface (Fig. 383), there may 

 be seen a deep groove opposite to and corresponding with the 

 attachment of the broad ligament (called the longitudinal 

 fissure], which lodges a fibrous cord (called the round liga- 

 menf). The anterior part of this cord (which passes backwards 

 to the liver from the navel) is the remnant of the primitive 

 umbilical vein, while the posterior part is similarly a relic of 

 the ductus venosus. On this account the anterior part of the 

 longitudinal fissure is called the umbilical fissure, while its pos- 

 terior part is named \h& fissure of the ductus venosus (Fig. 385). 



This longitudinal fissure then divides the liver into two 



unequal lobes on its under surface, and the larger of these 



lobes is again subdivided by other fissures. Thus a small 



prominent lobe (called Spigelian] is placed at the hinder 



G G 2 



