THE LIVER. 



1051 



This is seen as the most prominent part of the lobe when the lesser omentum is 

 divided in front. This lobe is the only part of the liver covered by the peritoneum 

 of the lesser sac. The finger goes under the caudate lobe, through the foramen 

 of Winslow, and passes up behind the Spigelian lobe. Above, it is limited by the 

 posterior layer of the coronary ligament ; to the right it is obstructed by the layer 

 of the lesser sac attached to the caval fossa ; and to the left the finger cannot pass 

 over to the stomach by reason of the double layer attached to the fissure of the 

 ductus venosus. All of the right lobe, except its posterior part, and all of the left 

 and quadrate lobes are covered by peritoneum of the greater sac. That on the 

 caudate is divided between the two sacs. 



Finally, to the extreme left of the posterior surface we have the thin posterior 

 edge of the left lobe sharply under-cut by the inferior surface. His regards the 

 tuber omentale as on the posterior surface. 



The anterior border is thin and sharp and marked opposite the attachment of 

 the falciform ligament by the umbilical notch (incisura umbilicalis), and opposite 

 the cartilage of the ninth rib by a second notch for the fundus of the gall-bladder 

 (incisura vesicalis). In adult males this border usually corresponds with the free 

 margin of the ribs; in women and children it may project below. 



The right extremity of the liver is thick and rounded, convex from before back- 

 ward and usually from above downward. Its upper and anterior angles are 

 rounded. Below it forms an acute margin with the under surface. 



The left extremity is thin and flattened from above downward. 



The fissures of the liver closely follow the lines of the letter H (Meckel), suppos- 

 ing them projected upon a flat surface (Fig. 667). They are five in number, 

 situated upon the inferior and poste- 

 rior surfaces of the liver, often called 

 fossce instead of fissures. The trans- 

 verse fissure, or porta hepatis (gate 

 of the liver), is the most important, 

 because the great vessels and nerves 

 enter here and the hepatic ducts and 

 lymphatics pass out. It is a short, 

 deep fissure, 5 cm. long (two inches) 

 and 12 to 15 mm. wide (one-half 

 inch) ; it is on the under surface of 

 the right lobe, passing transversely a 

 little nearer the posterior surface than 

 the anterior margin and nearer the 

 left extremity than the right. It 



separates the quadrate lobe in front from the caudate and Spigelian lobes behind, 

 and joins the two longitudinal fissures at nearly right angles. The two vertical 

 arms of the H are represented by the two longitudinal fissures, right and left. 



The left longitudinal, or sagittal, fissure (fossa longitudinalis sinistra) separates 

 the right from the left lobe, and is divided into an anterior and posterior part by 

 its junction with the transverse fissure. The anterior part is the umbilical fissure, 

 which contains the umbilical vein in the foetus and its remains in the adult, which 

 is then called the round ligament (Lig. teres). It lies between the quadrate and 

 left lobes of the liver. This fissure, and the one for the ductus venosus, are often 

 bridged over by liver tissue (pons hepatis), converting a fissure wholly or partially 

 into a canal. 



The posterior part of the left longitudinal fissure is not so marked as the ante- 

 rior part ; it passes between the lobe of Spigelius and the left lobe, and is called 

 the fissure of the ductus venosus. In the foetus it lodges a vein, but in the adult 

 this vein becomes a slender cord, lig. venosum. 



The right longitudinal fissure (fossa longitudinalis dextra) runs parallel to the 

 left one. and has an anterior and posterior part. It meets one interruption just 

 behind the transverse fissure, where the caudate lobe connects the Spigelian and 



FIG. 667. Diagram of fissures of liver. Schematic. 

 Seen from behind and below. 



