THE LIVEK. 1191 



(2) Fossa Venae Umbilicalis (O.T. Umbilical Fissure). The fossa for the umbilical 

 vein is a deep crevice-like fissure, situated in the inferior surface, running from 

 before backwards, parallel to the gall-bladder, but about 1 to 1J inches to its left 

 side. It begins in front at the margo anterior, which it intersects, and runs 

 backwards to the left extremity of the porta hepatis. Within this fissure lies a 

 rounded cord-like structure, the ligamentum teres hepatis, the remains of the left 

 umbilical vein of the foetus. The fissure is often crossed by a bridge of liver tissue, 

 the pons hepatis, which may even extend for the whole length of the fissure, and 

 conceal the round ligament from view. 



(3) Fossa Ductus Venosi. At the posterior termination of the fossa venae 

 umbilicalis the ligamentum teres is usually attached to the left branch of the portal 

 vein. Beyond that point it is continued backwards as a fine fibrous band, the 

 ligamentum venosum (Arantii), which runs onwards to join the vena cava inferior. 

 This fibrous cord is the remains of the ductus venosus, and it lies in a groove on 

 the posterior aspect of the liver, called the fossa for the ductus venosus. 



The umbilical vein and the ductus venosus in the foetus serve to convey the 

 blood back from the placenta to the inferior vena cava. 



The umbilical fossa and the fossa for the ductus venosus together form a 

 continuous fossa on the inferior and posterior surfaces which divides them into 

 a right and left lobe. This fossa is known as the fossa sagittalis sinistra, in 

 contrast to the porta hepatis, and to the fossa sagittalis dextra, lying to the right 

 of two fossae which is made up of the following two fossae : 



(4) Fossa Vesicse Fellese. The fossa for the gall-bladder is a slight depression 

 which begins (often as a notch) at or near the margo anterior of the liver, 

 and runs backwards and to the left, as far as the porta hepatis (Fig. 938). 

 Its surface is, as a rule, not covered by peritoneum, and in it lies the gall-bladder, 

 which is united to it by areolar tissue. 



(5) Fossa Venae Cavae. The fossa for the vena cava is a deep groove, on the 

 posterior surface, on the right side of the caudate lobe, in which the superior part 

 of the vena cava inferior is embedded, immediately before it pierces the diaphragm. 



The depressions for the gall-bladder and the vena cava are rightly called fossae. In hardened 

 specimens it will be seen that the fossa for the umbilical vein, the porta hepatis, and the fossa for 

 the ductus venosus are really fissures. 



Taken together, the five fossae are arranged somewhat in the form of the letter 

 A (Fig. 938) ; the two lower divisions of the diverging limbs being formed by the 

 fossa venae umbilicalis and the fossa vesicae fellese respectively, and the cross-piece 

 by the porta hepatis all of which are placed on the inferior surface. The two 

 upper divisions of the limbs are represented by the fossa ductus venosi and that of 

 the vena cava, which meet above and are both placed on the posterior surface. The 

 latter of these two namely, the fossa of the vena cava, represented by the right 

 upper division of the A does not join the cross-piece (the porta hepatis), but is 

 separated from it below by a narrow ridge of liver substance the processus caudatus 

 (Fig. 938). 



To the right of the A is the lobus hepatis dexter, to its left the lobus hepatis sinister. 



The interior of the A is filled by the lobus quadratus anteriorly and the lobus 

 caudatus [Spigeli] posteriorly, both of which are described as parts of the right lobe, 

 while the processus caudatus cuts across the stem of the A behind the cross-piece, 

 and connects the lobus caudatus (Spigeli) to the lobus hepatis dexter. 



Lobi Hepatis (Lobes of the Liver). As has been pointed out, the attachment 

 of the ligamentum falciforme to the superior surface of the liver divides that 

 aspect of the organ into right and left lobes. Similarly, upon the inferior surface, 

 " e fossa sagittalis sinistra is taken as dividing this aspect into right and left lobes. 



Lobus Hepatis Sinister. The left lobe is much smaller and flatter than the 

 .ght, and forms only about one-fifth of the whole mass. 



Lobus Hepatis Dexter. Its inferior and posterior surfaces of the right lobe are 

 intersected by the three additional fossae described above, and by them it is 

 subdivided into other parts, which also are called lobes. These are the lobus 

 caudatus [Spigeli] with the processus caudatus, and the lobus quadratus. 



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