306 SURGICAL APPLIED ANATOMY. [Chap. xvi. 



conjoined tendon is perforated by the hernia, or lastly 

 the gut deviates a little in an outward direction so as 

 to avoid the tendon and appear at its outer side 

 (Velpeau). In any case the hernia is forced almost 

 directly into the external abdominal ring. The 

 coverings of such hernise are the skin and superficial 

 fascia, the intercolumnar fascia, the triangular liga- 

 ment and conjoined tendon (with the exceptions above 

 mentioned), the transversalis fascia, subserous tissue, 

 and peritoneum. 



An examination of the abdominal wall, apart from 

 clinical experience, would lead one to suspect that the 

 direct hernia would be more common than the indirect, 

 since the parietes are certainly less resisting opposite 

 Hesselbach's triangle than they are in the parts imme- 

 diately external to the epigastric artery. Indeed, just 

 to the outer side of the conjoined tendon the belly wall 

 is remarkably thin. These conditions, however, seem 

 to offer less facilities for the escape of a hernia than 

 does the inguinal canal itself. The funnel-shaped 

 depression in the peritoneum at the summit of that 

 canal seems to offer particular inducements for rupture, 

 and there are, besides, certain congenital defects in the 

 vaginal process of the peritoneum that render hernia 

 almost unavoidable along the inguinal canal. 



Direct versus indirect inguinal hernia. 

 The indirect hernia, as just hinted, may be congenital, 

 the direct is never congenital In the congenital 

 oblique hernia the outline of the inguinal canal and 

 the relations of the various parts concerned are but 

 little disturbed, and the differences between this 

 form of rupture and the direct variety are conspicuous. 

 The acquired oblique hernia, however, does not present 

 such a contrast to the direct form as may be expected. 

 In the first-named rupture, from constant dragging 

 upon the parts the internal ring becomes more or less 

 approximated to the external ring, and the length of 



