PANCREAS. 



rnonly receives a large tributary branch, often 

 nearly as large as itself, coming from the head 

 of the pancreas. This occasionally remains 

 permanently distinct, and opens into the in- 

 testine by a separate orifice (see Jig. 55. B, 

 c), a condition always present, according to 



Fig. 55. 



A 



Diagram of the principal Varieties to which the ter- 

 mination of the pancreatic duct and its relation to 

 the bile-duct is liable in the human subject, arranged 

 in their order of frequency. 



A. The normal arrangement, showing a, the bile- 

 duct, and b, the pancreatic, terminating by one 

 orifice. 



B. Showing the separate termination of c, the ac- 

 cessory duct from the head, or lesser pancreas. 



c. The main duct, b, terminating by an orifice 

 distinct from the choledoch. 



D. Two parallel and equal ducts b, c, are here 

 seen joining the bile-duct at its orifice. This is a 

 case of " double pancreatic duct." 



Meckel, in the early foetus, so that this irre- 

 gularity is essentially nothing but an exten- 

 sion of a foetal condition into adult life. When 

 this duplicity of orifice exists, the separate 

 duct from the head of the pancreas has its 

 own little papilla, proportionately smaller 

 than the normal one, and separated from it 

 about fths of an inch or an inch. It is 

 usually lower down, though sometimes higher 

 up, than the main orifice. It has been ob- 

 served by Cruveilhier, that when there is one 

 duct opening by a distinct orifice appropriated 

 to itself alone, there is always another open- 

 ing into the duodenum in the normal way in 

 common with the ductus choledochus. Ac- 

 cording to other authorities*, however, the 

 pancreatic duct and the bile duct will some- 

 times open on the mucous membrane of the 

 duodenum by two entirely distinct orifices, 

 when the former is single and there is no 

 secondary one, as seen in Jig. 55. c. Oc- 

 casionally the pancreatic duct is double 

 throughout its whole length, the two running 

 side by side and communicating, just before 

 * Scemmerring, Corp. Human. Fabrica. 



their junction, with the ductus choledochus, 

 as shown in Jig. 55. D. Scemmerring asserts 

 that there are sometimes three diicts dis- 

 tinct throughout and opening separately. All 

 the varieties of method of termination of the 

 pancreatic duct have been collected and ana- 

 lysed by Tiedemann*; and he has come to the 

 interesting conclusion that they all have their 

 analogues in the different arrangements found 

 in the various species of the lower animals. 



The method of termination of the pancre- 

 atic duct, and its relation to the ductus cho- 

 ledochus, is rather curious. The duct, unlike 

 the ducts of the salivary glands, which have 

 a long course after leaving the gland before 

 they terminate, passes at once from the gland 

 to the intestine at a point where the former 

 is closely applied to the latter, so that it is 

 quite covered up and has no peritoneal in- 

 vestment. At this situation it comes into 

 contact, at an acute angle, with the ductus 

 choledochus, which has descended to this 

 point either in a groove of the pancreas, 

 between it and the intestine, or in a complete 

 channel through the gland substance. The 

 pancreatic is placed to the left of the choledoch 

 duct ; and, maintaining this relation, the two 

 perforate obliquely the duodenum about the 

 middle of its second portion and at the left 

 side of its posterior wall. 



Side by side they perforate in succession 

 the muscular, the fibrous, and the mucous 

 coats, which they elevate into a ridge when 

 injected or when a probe is passed into them, 

 and after an oblique course of about eight 

 lines, they open into the bottom of a little 

 papilla situated in a transverse fold near the 

 junction of the middle with the third portion 

 of the duodenum. f In their transit through the 

 walls of the intestine they are separated by a 

 valve-like process, composed of the tissues 

 that constitute their walls, which gradually 

 gets thinner and thinner till it terminates at 

 the base of the little olive-shaped ampulla 

 about two lines in depth, into which the 

 cavity of the papilla is dilated ; and since the 

 mucous membrane lining this ampulla is of 

 the same structure as that lining the intestine, 

 and unlike that lining the ducts, these latter 

 must be said to open by two distinct orifices 

 at the base of the papilla, and not by one at 

 its apex, as is usually described ; in fact the 

 lining membrane of the cavity of the papilla 

 is part of the general mucous surface of the 



* Sur les differences que le canal excre'teur du 

 pancreas pre'sente dans 1'homme et dans les mam- 

 miferes. Journal Compl. des Sciences Me'dicales, 

 torn. iv. p. 370. 



t The point of immergence of the pancreatic 

 duct is variously stated by various authors. Soan- 

 merriny gives it as from three to twelve fingers 

 breadth" o below the pylorus ; Meckel, from three to 

 four inches, but possibly amounting to ten ; Quain, 

 three to four inches ; Cruveilhier, at the lower part 

 of the second portion of the duodenum ; Ue Graaf, 

 quatuor digitis transversis sub pyloro ; Gavard, five 

 fingers breadth from the pylorus ; and so on. That 

 given in the text, which coincides with Cruveil- 

 hier, is the normal one ; the extremes are very ex- 

 ceptional. 



G 3 



