INTERNAL OR DIRECT HERNIA. 425 



The constituents of the abominal wall in this spot are, the teguments; 

 the strata of the muscles ; and the layers lining the interior of the abdo- 

 men, viz., fascia trans versalis, subperitoneal fat, and peritoneum. The 

 muscles have the undermentioned arrangement: The aponeurosis of the 

 external oblique is pierced by an aperture (external abdominal ring) towards 

 the lower and inner angle of the space through which the inguinal hernia 

 is transmitted. The internal oblique and transversalis, which come next, 

 are united together in the conjoined tendon ; as this descends to its in- 

 sertion into thepectineal line, it covers the inner two-thirds (about an inch) 

 of the space, and leaves uncovered about half an inch between its outer 

 edge and the epigastric vessels, where the fascia transversalis appears. 



Any intestine protruding in this spot must make a new path for itself, 

 and elongate the different structures, because there is not any opening by 

 which it can descend, as in the external hernia. Further, the coverings 

 of the bernia, and its extent and direction in the abdominal wall, must 

 vary according as the gut projects through the portion of the space covered 

 by the conjoined tendon, or through the part external to that tendon. 



Course and coverings of the hernia. The common kind of the internal 

 hernia (inferior) passes through the part of the triangular space which is 

 covered by the conjoined tendon. 



The intestine in protruding carries before it the peritoneum, the sub- 

 peritoneal fatty membrane, and the fascia transversalis ; next it elongates 

 the conjoined tendon, or as in a sudden rupture, separates the fibres, and 

 escapes between them. Then the intestine advances into the lower part 

 of the inguinal canal, opposite the external abdominal ring ; and passes 

 through that opening on the inner side of the cord, receiving at the same 

 time the covering of the fascias perrnatica. Lastly, it is invested by the 

 superficial fascia and the skin. 



In number the coverings of the internal hernia are the same as those of 

 the external ; and in kind they are the same, with this exception, that the 

 conjoined tendon is substituted for the cremasteric fascia. 



The position of the openings in the abdominal wall should be kept in 

 mind during attempts to reduce this kind of hernia ; and the straightness 

 of the course of the internal, in comparision with' the external hernia, 

 should be remembered. 



Diagnosis. This rupture will be distinguished from external hernia by 

 its straight course through the abdominal wall, and by the neck being 

 placed close to the pubes. 



After this hernia has acquired a large size, an examination during life 

 cannot determine whether it began originally in the triangular space, or 

 at the internal abdominal ring ; for as an external hernia increases, its 

 weight drags inwards the internal ring into a line with the external, and 

 in this way the swelling acquires the appearance of a direct rupture. 



Seat of stricture. The stricture in this form of hernia occurs most 

 frequently external to the neck of the tumor, though it may be inside 

 from thickening of the peritoneum ; and it may occasionally be found at 

 the external abdominal ring. 



Division of the stricture. The neck of the tumor is to be laid bare, 

 and all fibrous bands around it are to be divided without injury to the 

 peritoneum ; but if, after this has been done, the intestine cannot be put 

 backwards into the abdomen, the sac is to be opened, and the internal 

 constricting band is to be divided directly upwards on a director. 



In the operation on a large rupture appearing to be direct, the operator 



