THE LIVER 



1191 



extends but slightly to the left, being somewhat flattened from side to side, and elongated 

 vertically. This type may occur as a result of tight lacing, in which the liver is frequently 

 deformed. The part projecting below the right costal margin may form the so-called 'Riedel's 

 lobe.' All intermediate forms between these two types occur. Its position and relations will 

 also vary necessarily according to differences in size and shape. For example, in the wide type 

 and also in enlarged livers, the left lobe may extend over upon the spleen, a relation which is 

 constant during prenatal life. 



There may be supernumerary fissures, dividing the liver into additional lobes, as many as 

 16 having been described in an extreme case (Moser). These extra fissures often correspond 

 to fissures which are normal in other mammals. There may also be accessory lobes, usually 

 small, and connected with the main gland by stalks. Any one of the normal lobes may be 

 atrophied or absent. There may also be abnormal grooves on the parietal surface of the liver. 

 Of these, there are two varieties: (1) costal grooves, due to impressions of the overlying ribs 

 and costal cartilages; and (2) diaphragmatic grooves, due to wrinkles in the diaphragm. These 



Fig. 953. — The Viscera of the Fcetus. (Riidinger.) 



Thyreoid 



Lung 



Liver 

 Falciform ligament 



Small intestine 



Bladd 



Trachea 



,Thymus 



Lung 



Right atrium 



Right ventricle 



Stomach 



Part of transverse colon 



Hypogastric artery 



grooves most frequently occur in females, as a result of tight lacing. The appendix fibrosa 

 has already been mentioned. There are numerous variation in the vascular arrangements, as 

 well as in the peritoneal relations (particularly in connection with the coronary ligament). 



The bile passages are even more variable than the liver proper. The gall-bladder is variable 

 in size and capacity (25 cc. to 50 cc. or more), as well as in its position and relations. The 

 fundus projects to a variable extent beyond the anterior margin of the liver so as to come into 

 contact with the abdominal wall in a little more than half the cases, but is often retracted. The 

 fossa of the gall-bladder is of variable depth, rarely so deep that it reaches the superior surface 

 of the liver. The peritoneum usually covers only the sides and inferior surface of the gall- 

 bladder, but occasionally surrounds it entirely, forming a short 'mesentery.' In rare cases 

 the gall-bladder is bifid or double, and is occasionally absent. There are numerous variations in 

 the bile-ducts. Rarely the hepatic ducts may communicate directly with the gall-bladder. 

 The point at which hepatic and cystic ducts unite is variable, which affects the relative lengths 

 of these and the ductus choledochus. The latter may open into the duodenum separately, 

 instead of with the pancreatic duct. 



