382 THE LIVER. 



Lobes. — The right and left lobes are separated from each other on 

 the under surface by the longitudinal fissure, and in front by the inter- 

 lobular notch : on the convex surface of the liver there is no other indi- 

 cation of a separation between them than the line of attachment of the 

 broad ligament. ■ The right lobe is much larger and thicker than the 

 left, which constitutes only about one-fifth or one-sixth of the entire 

 gland. 



The lobulus quadratus (anonymus) (fig. 273, 6) is situated be- 

 tween the gall-bladder and the great longitudinal fissure, and in front 

 of the portal or transverse fissure. ' It is somewhat oblong from before 

 backwards. 



The lobulus Spigelii(8, 9, 10), more prominent and less regular in 

 shape than the quadrate lobe, lies behind the fissure for the portal vein, 

 and is bounded on the right and left by the fissures which contain the 

 inferior vena cava and the remains of the ductus venosus(2r), ly). 



The lobulus caudauus(ll) is a sort of ridge which extends from 

 the base of tlie Spigelian lobe to the under surface of the right lobe. 

 This, in the natural position of the parts, passes forwards above the 

 passage named foramen of Winslow, the Spigelian lobe itself being 

 situated behind the small omentum, and projecting into the omental sac. 



Fissures. — The transverse or portal fissure (fig. 273, 12, 13) is tlic 

 most imi)ortant, because it is here that the great vessels and nerves 

 enter, and the hepatic duct passes out. It lies transversely between the 

 lobulus quadratus and lobulus Spigelii, and meets the longitudinal 

 fissure nearly at right angles. At its two extremities, the right and 

 left divisions of the hepatic artery and portal vein, together with 

 the nerves and deep lymphatics, enter the organ, while the right and 

 left hepatic ducts emerge. 



The longitudinal fissure, between the right and theleft lobes, is divided 

 into two parts by its meeting with the transverse fissure. The anterior 

 part (16), named the umbilical fissure, contains the umbilical vein in 

 the foetus, and the remnant of that vein in the adult, which then con- 

 stitutes the round ligament (17). It is situated between the square and 

 the left lobe of the liver, the substance of which often forms a bridge 

 {pons liepaUs) across the fissure, so as to convert it partially or completely 

 into a canal. The posterior part (18) is named the fissure of the ductus 

 venosus {fossa ductus vcnosi) ; it is situated between the lobe of Spi- 

 gelius and the left lobe and lodges the ductus venosus in the foetus, and 

 in the adult a slender cord or ligament (19) into which that vein is 

 converted. 



The fissure or fossa of the vena cava (25) is situated at the back 

 part of the liver, between the Spigelian lobe and the right lobe, 

 and is separated from the transverse fissure by the caudate lobe. It 

 is prolonged upwards in an oblique direction to the posterior border 

 of the liver, and may be said to join behind the Spigelian lobe with the 

 fissure for the ductus venosus. It is at the bottom of this fossa that 

 the blood leaves the liver by the hepatic veins, which end here in the 

 vena cava. As in the case of the umbilical fissure, the substance of the 

 liver in some cases unites around the vena cava, and encloses that vessel 

 in a canal. 



The last remaining fissure, or rather fossa {fossa cijstis fellecv), is 

 that for the lodgment of the gall-hladder (21) ; it is sometimes continued, 

 into a slight rounded notch on the anterior margin of the liver. 



