1720 



HUMAN ANATOMY. 



part, empty into the nodes in the portal fissure. Some open into a node said to 

 lie in the angle at the bend of the neck. 



The nerves are from the solar plexus through the hepatic plexus. 

 The peritoneal relations of the bladder and ducts are considered with those of 

 the liver (page 1721). 



The cystic duct (ductus cysticus), 3 or 4 cm. in length, with a diameter of 

 from 2-3 mm. , passes in a fold of peritoneum from the neck of the gall-bladder to 

 the gastro-hepatic omentum, where it joins the hepatic duct at an acute angle or, 

 rather, opens into its side. It is said sometimes to present an enlargement at its 

 end. In its natural condition it looks externally like the other ducts, but if distended 

 and dried it presents a series of irregular folds giving the impression of a spiral fold 

 which, in the adult at least, a closer inspection does not confirm. 



Structure. In structure the cystic duct presents much more of a muscular 

 layer than the others. This is thickest at the upper part, and consists chiefly of 

 circular fibres. These enter, especially near the beginning, the valvular folds of the 

 mucous membrane, which is clothed with simple columnar epithelium. In the foetus 

 there is a fairly distinct spiral valve, most developed in the upper part, and, in fact, 

 starting in the neck of the gall-bladder. Later the continuous spiral ridge (valvula 



spiralis Heisteri) usually atro- 

 phies and is broken up at many 

 places, leaving detached folds 

 with a semilunar outline and 

 no longer distinctly spirally ar- 

 ranged. Little pockets also de- 

 velop between them. Small 

 tubular glands are few in the 

 upper part, but plentiful in the 

 lower. 



The common bile-duct 

 (ductus choledochus) is about 

 7 cm. (2^4 in.) long. Its diam- 



FIG. 



Bile-due 



Papilla 



Pancreati' 

 duct 

 Frenum 



Ampulla 



Pancreatic 

 duct 



A, portion of duodenum, with anterior wall removed, showing 

 entrance of bile and pancreatic ducts; B, papilla laid open, showing 

 floor of ampulla. One-half natural size. 



eter is from 67 mm. at the 

 commencement and rather less 

 at the end. Beginning imme- 

 diately below the transverse 

 fissure, although conventionally 

 regarded as formed by the union 

 of the cystic and the hepatic 

 ducts, being, in fact, the direct 

 continuation of the latter, the 

 common bile-duct passes down- 

 ward between the layers of 

 the gastro-hepatic omentum, in 

 front of the foramen of Winslow, with the hepatic artery to its left and the portal 

 vein behind. It descends along the postero-inner aspect of the bend joining the 

 first and second parts of the duodenum, then along the inner side of the second part, 

 where it is more or less surrounded by the head of the pancreas. Near its termina- 

 tion it meets the pancreatic duct and, in company with the latter, pierces the duo- 

 denal wall, which it traverses obliquely for the distance of some 15 mm., to empty 

 into the duodenum at a papilla marking the common orifice of the two ducts. This 

 papilla is situated near the posterior border of the internal aspect of the descending 

 part of the duodenum, from 9-10 cm. (about 3^-4 in.) from the pylorus. In the 

 natural condition it is not easy to find, being situated beneath a transverse fold and 

 not being prominent in the shaggy mucous membrane. Its length umlistended is 

 Only about 5 mm. When inflated or injected it is a prominent object more than 

 twice as large. M.-rei.ver. it does not project freely, but lies on its side pointing 

 downward, the surface next to the wall becoming free only very near its end. The 

 orifice looks downward. It may be oval or circular, with a diameter of from 1-2 mm. 

 A slight vertical fold, the frenum, often runs downward from the opening for the 



