238 ANATOMY OF THE ABDOMEN. 



THE LIVER. 



The liver (Plate IV. J) is so bulky and ponderous a mass, 

 that there seems great wisdom in placing it in the centre of 

 the body. Anatomically its larger part is situated in the 

 right hypochondrium ; a smaller portion in the left (see Plate 

 ly.), and its centre in the epigastrium; in circumference 

 it is between two and two and a half feet ; thick towards the 

 middle, but thinner at the edges. It is divided into two 

 large and several smaller lobes ; which are again further sub- 

 divided by indentations, the principal of which separates the 

 two large lobes, and is called the great fissure : within this 

 may be seen the remains of the foetal umbilical vein ; while 

 a smaller indentation, seen about the centre of the concave 

 surface, forms an opening for the portse. By its convex 

 surface the liver is attached to the diaphragm by cellular 

 tissue and peritoneum, which last being reflected over it, 

 sustains it. Numerous lymphatics run over its surface ; and 

 the bloodvessels pass within its sheath called Glisson's 

 capsule. Ghsson's capsule is a thin membrane, formed of 

 white fibrous tissue, and situated immediately beneath the 

 peritoneum. The principal bloodvessels of the hver are the 

 vena portee, which carries to the gland the venous blood 

 fi'om the intestines; vena hepatica, and arteria hepatica, 

 which last is concerned directly in the nourishment of the 

 liver. Its nerves are derived from the hepatic ganglion, 

 which is principally composed by branches derived from 

 the sympathetic and par vagum. 



Vena porta hepaticce .—The circulation of the venous 

 blood in the liver presents a remarkable speciality, as may 

 be gained by what follows. The numerous veins of the in- 

 testines all terminate in one common trunk, which enters 

 the liver as the vena portse. This venous trunk, after it 

 has pierced the liver, branches ofl" once more in every direc- 

 tion to be ramified throughout the substance of the gland ; 

 it necessarily performs the office of an artery, being dis- 

 tributed to the liver for secretion. The blood being circu- 

 lated through the substance of this viscus, and acted on 

 within it, is poured from the terminations of the vena portce 

 and hepatic artery, into the hepatic veins, which empty their 

 contents into the posterior cava by numerous branches. 



