78 INGUINAL HERNIA. 



testicle; but the testicle passes obliquely downwards and inwards 

 for an inch and a half, until it gets opposite the external abdominal 

 ring, which is a hole, and at which, it emerges between its columns 

 or pillars. The fact, that in health these two rings are not opposite, 

 contributes much to the strength of the arrangement, and preventing 

 the more frequent occurrence of hernia, which is much favoured by 

 a deficiency in the fibrous character of the tendon of the external 

 oblique. 



The space between these two rings, is called the inguinal, ahdo- 

 ininal, or spermatic canal. It is bounded anteriorly by the inferior 

 edge of the internal oblique and transversalis muscles, the tendon of 

 the external oblique, the superficial fascia, and skin ; posteriorly by 

 the transversalis fascia, and the conjoined tendon of the transversalis 

 and internal oblique muscles; inferiorly, by Poupart's ligament. 



When the hernia does not emerge from this canal, it is called a 

 concealed inguinal hernia. 



At the external abdominal ring, the testicle, with its covering, 

 comes in contact with the superlicial fascia, which has already 

 been described as consisting of numerous laminse, one of which 

 can readily be shown to extend between the columns of the ring, and 

 hence it is called the intercolumnar fascia by some, by others, the 

 external spermatic, &c. This fascia, pushed before the testicle, 

 assists in forming that covering already alluded to, the fascia pro- 

 pria, or tunica vaginalis, comniioiis. That portion of the fascia 

 transversalis engaged in forming this cellular coat of the testicle, is 

 actually blended with the superficial fascia of the testicle, on account 

 of the intervening muscular structure, that of the cremaster being 

 deficient in some parts, and very spare in others. Hence a confu- 

 sion in authors and terms, some attributing this covering of the tes- 

 ticle to the transversalis fascia, and some to the superficial fascia, 

 whereas in fact it is formed partly by both. 



The skin is, of course, readily traced from the abdomen to the 

 scrotum, although in the scrotum it is modified by the dartos, which, 

 according to some, is an expansion of the gubernaculum testis. 



We have seen the changes which take place in the descent of the 

 testicle, and are now prepared to consider the escape of the intestine. 



The convolution or knuckle of intestine first presses against the 

 peritoneum, and being contained within the cavity, can only 

 push before it a single lamina. This portion of the peritoneum 

 always forms the hernial sac^ which gradually increases in size and 

 thickness. In this variety of hernia, (oblique inguinal), the protru- 

 sion takes place at the internal ring ; the sac must then necessarily 

 be covered by the transversalis fascia and cremaster muscle, and 

 after passing down the inguinal canal, emerges at the external abdo- 

 minal ring, where it receives an additional investment of superficial 

 fascia and skin. 



