THE LIVER. 677 



one-third from its posterior extremity, and divides it into two parts. The anterior 

 half is called the umbilical fissure; it is deeper than the posterior part, and lodges 

 the umbilical vein in the foetus, or its fibrous cord (the round ligament) in the 

 adult. This fissure is often partially bridged over by a prolongation of the hepatic 

 substance, the pans hepatis. 



The fissure of the ductus venosus is the back part of tho longitudinal fissure; 

 it is shorter and shallower than the anterior portion. It lodges in the foetus the 

 ductus venosus, and in the adult a slender fibrous cord, the obliterated remains of 

 that vessel. 



Fig. 342. The Liver. Under Surface. 



The transverse or portal fissure is a short but deep fissure, about two inches 

 in length, extending transversely across the under surface of the right lobe, nearer 

 to its posterior than its anterior border. It joins, nearly at right angles, with the 

 longitudinal fissure. By the older anatomists, this fissure was considered the 

 gateway (porta) of the liver ; hence the large vein which enters at this point was 

 called the portal vein. Besides this vein, the fissure transmits the hepatic artery 

 and nerves, and the hepatic duct and lymphatics. At their entrance into the 

 fissure, the hepatic duct lies in front to the right, the portal vein behind, and the 

 hepatic artery between the other two to the left. 



The fissure for the gall-bladder (fossa cystidis fellese) is a shallow, oblong 

 fossa, placed on the under surface of the right lobe, parallel with the longitudinal 

 fissure. It extends from the anterior free margin of the liver, which is occa- 

 sionally notched for its reception, to near the right extremity of the transverse 

 fissure. 



The fissure for the vena cava is a short deep fissure, occasionally a complete 

 canal, which extends obliquely upwards from a little behind the right extremity 

 of the transverse fissure, to the posterior border of the organ, where it joins the 

 fissure for the ductus venosus. On slitting open the inferior vena cava which 

 is contained in it, a deep fossa is seen, at the bottom of which the hepatic veins 

 communicate with this vessel. This fissure is separated from the transverse 

 fissure by the lobus caudatus ; and from the longitudinal fissure by the lobus Spi- 

 gelii. 



LOBES. The lobes of the liver, like the ligaments and fissures, are also five in 

 number ; the right lobe, the left lobe, the lobus quadratus, the lobus Spigelii, and 

 the lobus caudatus. 



The right lobe is much larger than the left ; the proportion between them being 



