7IO A MANUAL OF ANATOMY 



from the cystic fossa. The gall-bladder measures about 3 inches 

 in length, its breadth at the widest part being i| inches. Its 

 capacity is from i to i| ounces. For the structure of the gall- 

 bladder, see Index. 



The cystic duct is about i| inches long, its diameter being about 

 ^L- inch. Its course is backwards, downwards, and to the left, and 

 it ends by joining the hepatic duct near the portal fissure to form 

 the common bile-duct. 



The common bile-duct (ductus communis choledochus) is formed 

 by the union of the hepatic and cystic ducts near the portal fissure. 

 Its length is fully 3 inches, its diameter being about J inch. It passes 

 downwards between the two layers of the gastro-hepatic omentum 

 in front of the foramen of Winslow, where it has the hepatic artery 

 on its left side, and the vena portae behind. It afterwards descends 

 behind the first part of the duodenum, and subsequently between 

 the second part of the duodenum and the head of the pancreas on 

 their posterior aspect. It then enters the wall of the second part 

 of the duodenum in company with the duct of the pancreas, and 

 runs obliquely in the wall for | inch. Thereafter it joins the pan- 

 creatic duct, and the resulting duct forms a dilatation, called the 

 ampulla of Vater, which, having become constricted, pierces the 

 mucous membrane and opens on the tip of the bile-papilla at the 

 junction of the inner and posterior walls of the second part of the 

 duodenum, where the upper two-thirds and lower third of that part 

 meet. The distance of this opening from the pylorus is about 

 4 inches. The common bile-duct sometimes opens into the 

 duodenum independently of the pancreatic duct, but close to it. 



It is in the ampulla of Vater where a gall-stone may become 

 lodged and delayed in its downward progress towards the 

 duodenum. 



Liver in Early Life. — The size of the liver in early life is much greater than 

 in the adult, the left lobe in particular assuming large dimensions. As age 

 advances, however, the left lobe undergoes a marked diminution in size. 



For the structure and development of the liver, see Index. 



Peritoneum. — ^The peritoneum is the serous membrane which 

 lines the abdominal parietes, and invests more or less com- 

 pletely most of the viscera. It is composed of two layers, parietal 

 and visceral, the contiguous surfaces of which are smooth and 

 moist. In the male the interval between the two layers forms a 

 shut sac, but in the female, at the fimbriated extremity of each 

 Fallopian tube, the sac communicates with the lumen of that tube, 

 and through it with the cavity of the uterus and the vagina. It is 

 at the margin of the fimbriated extremity of each Fallopian tube 

 where the endothelium of the peritoneum undergoes a sudden 

 transition into the columnar ciliated epithelium of the Fallopian 

 tube. 



The peritoneum forms certain reflections or folds which are ol 

 three kinds, namely, omenta, mesenteries, and ligaments. 



