86 i THE LIVER. 



smaller and flatter, by the line of attachment of the fold of peritoneum 

 named the falciform ligament. 



The under surface, looking downwards and backwards, is concave and 

 uneven, invested with peritoneum everywhere except where the gall-blad- 

 der is adherent to it, and at the portal fissure and fissure of the ductus 

 venosus, which give attachment to the small omentum, the fold of peri- 

 toneum which passes round the blood-vessels and ducts of the viscus. On 

 this surface the lobes and fissures of the liver are observed. 



The lobes of the liver, five in number, are named the right and the left, 

 the lobe of Spigelius, the caudate or tailed lobe, and the square lobe. 



The right and left lobes are separated from each other on the under sur- 

 face by the longitudinal fissure, and in front by the interlobular notch : 

 on the convex surface of the liver there is no other indication of a sepa- 

 ration 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 other three lobes are small, and might be said to form parts of the 

 right lobe, on the under surface of which they are situated. 



The lobulus quadratus is that part which is situated between the gall- 

 bladder and the great longitudinal fissure, and in front of the fissure for the 

 portal vein. Its greatest diameter is from before backwards. 



The lobulus Spigelii, 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. 



The lobulus caudatus is a sort of ridge which extends from the base of 

 the Spigelian lobe to the under surface of the right lobe. This, in the 

 natural position of the parts, passes forwards above the foramen of Wins- 

 low, the Spigelian lobe itself being situated behind the small omentum, and 

 projecting into the omental sac. 



The fissures. These are likewise five in number, and are seen on the 

 under surface only. They have all been already incidentally referred to. 



The transverse fissure, or portal fissure, is the most important, be- 

 cause 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 the two extremities of this fissure, the right and left divisions of the 

 hepatic artery and portal vein, together with the nerves and deep lympha- 

 tics enter the organ, while the right and left hepatic ducts emerge. 



The longitudinal fissure, which separates the right and the left lobes 

 of the liver from each other, is divided into two parts by its meeting 

 with the transverse fissure. The anterior part, named the umbilical fissure, 

 contains the umbilical vein in the foetus, and the remnant of that vein 

 in the adult, which then constitutes the round ligament. It is situated 

 between the square lobe and the left lobe of the liver, the substance of 

 which often forms a bridge across the fissure, so as to convert it partially 

 or completely into a canal. The posterior part is named the fissure of the 

 ductus venosus (fossa ductus venosi) ; it continues the umbilical fissure back- 

 wards between the lobe of Spigelius and the left lobe ; and it lodges the 

 ductus venosus in the foetus, and in the adult a slender cord or ligament 

 into which that vein is converted. 



The fissure or fossa of the vena cava is situated at the back part of the 

 liver, between the Spigelian lobe on the left and the right lobe, and is 



