INGUINAL HERNIA. 267 



jie abdomen into the spermatic canal, through the internal abdominal nng, 

 pressing before it a pouch of peritoneum which constitutes the hernial sac, 

 and distending the infundibuliform process of the transversalis fascia. 

 After emerging through the internal abdominal ring, it passes first beneath 

 the lower and arched border of the transversalis muscle ; then beneath the 

 lower border of the internal oblique muscle; wc\<\ finally through the ex- 

 ternal abdominal ring in the aponeurosis of the external oblique. From 

 the transversalis muscle it receives no investment ; while passing beneath 

 the lower border of the internal oblique it obtains the cremaster muscle ; 

 and, upon escaping at the external abdominal ring, receives the inter- 

 columnar fascia. So that the coverings of an oblique inguinal hernia, 

 after it has emerged through the external abdominal ring, are, from the 

 surface to the intestine, the 



Integument, Cremaster muscle, 



Superficial fascia, Transversalis, or infundibuliform fascia, 



Intercolumnar fascia, Peritoneal sac. 



The spermatic canal, which, in the normal condition of the abdominal 

 parietes serves for the passage of the spermatic cord in the male, and the 

 round ligament with its vessels in the female, is about one inch and a 

 half in length. It is bounded in front by the aponeurosis of the external 

 oblique muscle '^behind by the transversalis fascia, and the conjoined ten- 

 don of the internal oblique and transversalis muscle ; above by the arched 

 borders of the internal oblique and transversalis; below by the grooved 

 oorcler of Poupart's ligament, and at each extremity by one of the abdo- 

 minal rings, the internal ring at the inner termination, the external ring at 

 the outer extremity. These relations may be more distinctly illustrated 

 by the following plan 



Above. 



Lower borders of internal oblique 

 and transversalis muscle. 



In Front. Behind. 



Transversalis fascia. 



Aponeurosis of exter 

 nal oblique. 



Spermatic canal. 



Belmv. 



Grooved border of 

 Poupart's ligament. 



Conjoined tendon of 

 internal oblique and 

 transversalis. 



There are three varieties of oblique inguinal hernia : common, congen- 

 ital, and encysted. 



Common oblique hernia is that which has been described above. 



Congenital hernia results from the nonclosure of the pouch of peritoneum 

 carried downwards into the scrotum by the testicle, during its descent in 

 the foetus. 



The intestine at some period of life is forced into this canal, and de- 

 scends through it into the tunica vaginalis where it lies in contact with the 

 testicle; so that congenital hernia has no proper sac, but is contained 

 within the tunica vaginalis. The other coverings are the same as thoso 

 of common inguinal hernia. 



Encysted hernia (hernia infantilis, of Hey) is that form of protrusion in 

 which the pouch of peritoneum forming the tunica vaginalis, being only 

 partially closed, and remaining open externally to the abdomen, admits 



