532 SPECIAL PHYSIOLOGY. 



facilitated. At certain points, this serous membrane passes, in the 

 form of folds, to the abdominal walls, and thus aids in supporting or 

 suspending the liver. These folds constitute four of the five ligaments 

 of the liver. The broad, suspensory, or falciform ligament is a trian- 

 gular double fold, attached by one border to the diaphragm, and to 

 the anterior wall of the abdomen as far as the umbilicus, and by the 

 other, to the upper surface of the liver, as far as the notch in its ante- 

 rior margin; the remaining border is free, and extends from the notch 

 in the liver to the umbilicus. This latter border contains a dense 

 fibrous cord, named the round ligament, ligamentum teres, Fig. 96, a, 

 which is formed by the remains of the umbilical vein, a structure which 

 becomes obliterated after birth. A considerable portion of the thick 

 posterior border of the liver is attached, by areolar tissue, to the dia- 

 phragm, and is therefore not covered by peritoneum, which, instead, 

 passes from one part to the other, forms the so-called coronary liga- 

 ment, and thus helps to suspend the liver to the diaphragm. The right 

 and left lateral ligaments are triangular peritoneal folds, strengthened 

 by intermediate fibrous tissue, which pass from eagch side of the liver 

 to the diaphragm. 



The liver is described as consisting of five lobes. Thus, it is di- 

 vided by the notch in its anterior margin, and by the line of attach- 

 ment of the suspensory ligament to its upper surface, into a right, I, 

 and left lobe l f , the former being quadrangular in shape and the latter 

 somewhat triangular, and constituting only about one-fifth of the en- 

 tire organ. A deep fissure on the under surface also marks the limit 

 between these lobes. On its under surface, the right lobe is further 

 divided into the following smaller lobes, viz., the Spigelian lobe, a py- 

 ramidal mass, situated near the hinder border ; the caudate or tailed 

 lobe, passing forwards from the Spigelian lobe ; and, lastly, the square 

 or quadrate lobe, placed between the gall-bladder and the line of de- 

 marcation between the right and left lobes. 



The liver also presents, on its under surface, five fossce or fissures, 

 in which are contained important vessels and ducts. The longitudinal 

 fissure passes, from before backwards, between the right and left lobes, 

 and is divided into two parts ; the anterior part is named the umbilical 

 fissure, which contains before birth the umbilical vein, but afterwards, 

 the round ligament, the fibrous cord left after the obliteration of that 

 vein; the posterior part, called the fissure, of the ductus venosus, con- 

 tains, before birth, the large vein so named, and subsequently the 

 fibrous cord remaining after its closure. Thirdly, extending nearly 

 at right angles from the junction of the umbilical fissure with the 

 fissure of the ductus venosus, to about the centre of the right lobe, is 

 the transverse or portal fissure, or porta, the gate, sometimes called the 

 hilus of the liver; through this the chief bloodvessels, lymphatics, 

 nerves, and ducts of the liver pass in and out (see Fig. 96). The prin- 

 cipal vessel which enters here, is a large vein, the vena portce or portal 

 vein. The fourth fissure is the notch on the posterior border of the 

 liver, which joins the fissure for the ductus venosus, and lodges the 

 ascending vena cava and the orifices of the so-called hepatic veins. 

 The fifth fissure receives the upper side of the gall-bladder. 



