PRACTICAL CONSIDERATIONS : THE SMALL INTESTINE. i6=; 



03 



Fig 



Entering layer 



Intussusceptuin 



wise its lower portion — the most fixed part of the intestine — would probably be more 

 often injured. The upper portion of the jejunum, which partakes somewhat of this 

 fixity, is more commonly ruptured than any other part. So, too, the most fixed 

 part of the ileum — that nearest the ileo-csecal junction — is most often the site of rup- 

 ture. An incarcerated or irreducible hernia may constitute a fixed point of the gut 

 and favor its rupture elsewhere from trauma to the surface of the abdomen. 



Ruptures of the intestine, like wounds or obstruction, are more serious the 

 higher they are situated. The nervous disturbance and shock are greater, possibly 

 on account of the more immediate relation of the lesion and of the resulting patho- 

 logical changes to the great nerve-plexuses or to the pericardial portion of the dia- 

 phragm (Crile) ; vomiting begins earlier and is more severe for the same reason ; 

 peristalsis is more vigorous (as the muscular coat of the gut is better developed) 

 and therefore rapid extravasation of intestinal contents is more likely and spontane- 

 ous closure of a wound less likely to occur ; and, if the condition is at all chronic,, 

 nutrition is interfered with to a greater extent. Clinical experience shows that in 

 such injuries the anatomical are more potent than the purely bacteriological factors, 

 which would tend to make jejunal wounds less dangerous than those lower in the 

 tract. Investigation has shown ( Cush- 

 ing and Livingood, and later Lorrain 

 Smith and Tennant) that the bacterial 

 flora in the upper portion of the intestinal 

 Iract is more scanty than in the lower 

 portion ; and it is true that peritonitis 

 following intestinal wounds, operative or 

 accidental, is dependent for its charac- 

 teristics upon the bacteria at the site of 

 lesion, and that the prognosis should be 



favorable in proportion to the scarcity | ^|^%^^ '111 ^^^;^^Returnin§; 



and innocuousness of the micro-organ- 

 isms present. But the anatomical con- 

 ditions, by adding to shock, favoring 

 intestinal extravasation, and minimizing 

 the chance of a reparative peritonitis, are 

 more than sufficient to counterbalance 

 the relative dearth of bacteria. 



It should be remembered that the 

 position of the wound or contusion on the 

 surface of the abdomen is of but slight 

 value in determining the area of gut in- 

 volved. Thus, a jejunal fistula following 

 a wound was situated midway between 

 the umbilicus and pubes, but measurements made by attaching ligature silk to portions 

 of food swallowed and extruded at the fistula showed that the latter was but 119 cm. 

 (3 ft. II in. ) from the incisor teeth> and was therefore high in the jejunum (Cushing. ) 



It may be noted that fistulae so situated are apt to be complicated by excessive 

 dermatitis, supposed to be due to the presence of pancreatic juice in the discharge, 

 as gastric, biliary, and colonic fistulae do not give rise to this trouble in any such 

 degree of severity. 



Obstruction of the small intestine may be due to {a) fo7-eign bodies (including 

 intestinal concretions and gall-stones that have ulcerated into the duodenum), and 

 is then most apt to occur at the ileo-caecal junction on account of the narrowing of 

 the canal at that point ; {b') bands, producing constriction of a coil or knuckle 

 of gut, such bands arising from the elongation of adhesions due to previous perito- 

 nitis, from inflammatory attachment of the free end of Meckel's diverticulum (page 

 1652), of adventitious diverticula (from protrusion of the mucous membrane through 

 the muscular coat), or of the appendix. Either the Fallopian tubes, the appendices 

 epiploicae, the omentum, or the mesentery may in like manner become converted 

 into constricting bands ; {c) stricture,, as from tuberculous ulcer in the ileum or 

 syphilitic ulcer in the jejunum ; (^) volvulus, especially in the lower part of the' 



Intussuscipien 



Ensheathing 

 layer 



•Jtiip 



Longitudinal section of intiissuscepted gut, showing 

 layers. 



