1 88 Anatomy Applied to Medicine and Smgery. 



thus tending to force apart, wedge-like, the fossa; (4) 

 the vas deferens and the spermatic vessels, converging to 

 meet in one of these fossae, viz., the external, guide, to 

 some extent, the intestines towards the internal ring. 

 For these reasons, then, hernia affects the inguinal region, 

 and especially that particular portion of it, viz., the inter- 

 nal abdominal ring, more frequently than it does any other 

 situation, and would be quite common were it not for the 

 protection and support afforded this region by the inter- 

 nal oblique muscle. 



Varieties of Hernia. When pressure is applied 

 to the abdominal contents and when the bowel impinges on 

 the external fossa, i.e., to the outer side of the deep epi- 

 gastric artery, and, when, for some reason, or, other, the 

 supporting wall is weakened, or, is not strong enough to 

 withstand the pressure, a knuckle of intestine distends the 

 peritoneal coat, and, stretching the infundibuliform fascia, 

 enters the canal. It cannot pass forward on account of 

 the aponeurosis of the external oblique, and, since there is 

 established already a line of less resistance by the presence 

 of the spermatic cord, it follows, that the most natural 

 passage for the protrusion will be .down, along the cord, to 

 the scrotum, resulting in the condition termed, acquired 

 inguinal hernia. The neck of the sac in this form will be 

 on the outer side of the deep epigastric artery, and is, 

 therefore, termed, external inguinal hernia, although the 

 name usually given to it is oblique inguinal hernia. Ac- 

 cording to statistics, this variety forms about ninety-three 

 per cent, of inguinal hernise. Should, however, the 

 protrusion occur internal to the deep epigastric artery, it is 

 termed internal or direct inguinal hernia and the bowel 

 may enter the inguinal canal some distance to the outer 

 side of the external ring, or, may appear, primarily, oppo- 

 site that ring. In direct inguinal hernia, the protrusion, 



