PRACTICAL CONSIDERATIONS : ABDOMINAL HERNIA. 1759 



sion to other peritoneal surfaces have been utilized in an operation for the relief of the 

 portal congestion in certain forms of hepatic cirrhosis (page 1727). 



The Mesentery. — The length of this portion of the peritoneum is of importance 

 in its relation to the causation and the forms of hernia, in connection with which it 

 will be referred to. From its oblique attachment it results, that in an intraperitoneal 

 right-sided hemorrhage the blood is first conducted into the right iliac fossa ; if the 

 hemorrhage takes place to the left of the mesentery, the blood descends directly into 

 the pelvis (Treves). Collections of blood are said to be more common in the right 

 than in the left iliac fossa. Treves has shown that, in addition to certain slit-like 

 holes due to injury, there are others which are congenital defects in the mesentery, 

 and has called attention to the fact that the latter are round ; are in the lower ileum ; 

 are surrounded by an anastomotic arch between the ileo-colic branch of the superior 

 mesenteric artery and the last of the intestinal arteries ; that the area is often the seat 

 of atrophied peritoneum ; and that fat, visible blood-vessels, and glands are absent. 

 Hernice of knuckles of gut through this cribriform area of mesentery could occur 

 with comparative ease. 



The use of the mesentery as a means of recognition of a particular portion of gut 

 during operative procedures has been described (page 1657). 



The practical relations of the peritoyieal foss(Z and folds will be considered in the 

 section on hernia (page 1765). 



PRACTICAL CONSIDERATIONS : ABDOMINAL HERNIA. 



Abdominal hernia would be correctly defined, in the great majority of cases, as 

 the protrusion of any abdominal viscus from the cavity of the abdomen, and if the 

 term were limited to include protrusion of only portions of the small intestine. (jejunum 

 and ileum ) and of the omentum, it would still embrace by far the larger number of 

 herniae. Intra-abdominal herniae occur, however, in which a portion of the intestine 

 passes from the general into the lesser peritoneal cavity or into one of the various 

 peritoneal fossae or recesses. The resulting evil effects in both cases are due not to 

 the protrusion but to the secondary changes that follow the displacement of the gut 

 (incarceration, strangulation). It is well, therefore, to subdivide abdominal herniae 

 into external and internal^ and in the latter variety to recognize the necessary modifi- 

 cation of the above definition. 



External Hernia. — The general conditions that predispose to or actually produce 

 external hernia are those associated with ( i ) increased intra-abdominal pressure and 

 (2) decreased resistance of the abdominal wall. 



1. LTnder the former should be placed (a) occupations that necessitate much 

 muscular effort, particularly if it is in the direction of lifting heavy weights, or is ex- 

 erted while the person is in a stooping posture {^vide infra), or if, at the same time, 

 increased respiratory effort is required, so that during forced inspiration the diaphragm 

 aids in augmenting the outward pressure of the abdominal viscera ; {b) diseases 

 causing vesical or rectal tenesmus ; (c ) respiratory diseases producing chronic or 

 violent cougiiing, or inspiratory obstruction. 



2. Decreased resistance of the whole abdominal wall may be due to («) debili- 

 tating illness, {b) old age, (c) prolonged distention (ascites, abdominal tumor, 

 repeated pregnancies, i^d) excessive corpulence, or ((?) emaciation. The last two 

 causes are assumed to act as follows : with the occurrence of general emaciation, the 

 fatty tissue filling up the hernial orifices usually disappears, and these places, which are 

 already less resistant, become more yielding and relaxed ; with the rapid appearance of 

 obesity there is an increase in the amount of the subperitoneal areolar tissue, and this 

 consequently results in a greater mobility of the peritoneum. The traction of a rapidly 

 growing subperitoneal lipoma upon the peritoneum, to which it is tightly adherent, 

 is also a factor in the development of a hernial sac, although it does not follow that 

 this method of origin is frequent or, as Roser asserted, the usual one (Sultan). 



The disappearance of fat and connective tissue in emaciation has been thought 

 (Macready) particularly to favor the occurrence of femoral hernia. 



Other predisposing causes are as follows : Age. — Hernia is very common during 

 the first year of life. Its frequency then is probably due to {a) the existence of 



