VISCERAL ANATOMY. 1 39 



Retractor Ani arises from the sacro-ischiatic ligament and is 

 inserted into sides of rectum. 



Action, pulls rectum forward after defecation. 



LIVER. 



The liver is situated in the abdomen, in the right diaphragmatic 

 region. Its weight is eleven pounds. It has anterior and pos- 

 terior flattened surfaces; thick at its centre, thin on its edges. 



Lobes. 



Left (largest), right, Spigelian and middle. 

 Fissures. 



(i) A deep one for the posterior cava; (2) another in the centre 

 of its posterior surface for the portal vein and vessels; (3) one 

 for the oesophagus; (4) and one dividing the right and left lobes. 



Ligaments. 



(a) Anterior or coronary, from fissure for cava to phrenic centre. 



(b) Of left lobe, from left lobe to side of cesophageal orifice. 



(c) Of right lobe, from lumbar wall to right lobe. 



(d) Broad or suspensory, from middle lobe to upper part of 

 inferior abdominal wall. 



(e) Round, from umbilicus to middle lobe. It is a fibrous cord, 

 formed by the obliterated umbilical vein. 



Structure. 



Serous coat externally, covering it completely, except at the 

 anterior and posterior fissures and forming ligaments. 



Fibrous (Glisson's capsule), enters posterior fissure and follows 

 vessels, after forming an outer envelope for the whole organ. 



Parenchyma or essential secreting portion, consists of: 



Lobules (^V to T ^o inch in diameter), which comprise liver cells, 

 polygonal in shape, -^ to -%%-$ inch in diameter, with one or two 

 nuclei. They lie in a network of small vessels. 



Hepatic ducts begin between the liver cells, enter the peri-lobular 

 connective tissue, unite with others getting constantly larger, and 

 finally, by several branches from the different lobes, form the 

 ductus choledochus or great bile-duct. This ascends in the gastro- 

 hepatic omentum to the duodenum, which it penetrates six inches 

 from the pylorus, surrounded by a circular fold of mucous mem- 



