EXTERNAL OR OBLIQUE HERNIA. 289 



the scrotum, it has the additional coverings of the superficial fascia 

 and the skin. 



In a hernia which has passed the external abdominal ring, the seven in 

 coverings from without inwards are therefore the following : the 

 skin and superficial fascia, the spermatic and cremasteric fasciae 

 the infundibuliform fascia, the subperitoneal tissue, and the peri- 

 toneum or hernial sac. Two of the coverings, viz., the peritoneal iiov,-pro- 

 and subperitoneal, originate as the gut protrudes ; but the rest are 

 ready formed round the cord, and the intestine slips inside them. 

 The different layers become much thickened in a hernia that has 

 existed for some time. 



Di(iaiio.<i.*. If the hernia is small, and is confined to the wall of Howtodis- 



' IT i i -i tmguish it. 



the belly, it gives rise to an elongated swelling along the inguinal 

 canal. If it has proceeded farther, and entered the scrotum, it 

 forms a flask-shaped tumour with the large end below, and the 

 narrow neck occupying the inguinal passage. 



Should a hernia of this kind become strangulated, the seat of stricture : 

 stricture is placed usually at the internal abdominal ring, and may where 

 be produced either by a constricting fibrous band outside the narrowed 

 neck of the tumour, or by a thickening and contraction of the 

 peritoneum itself at the inner surface of the neck. 



Division of stricture. In division of the stricture, with the view of To relieve, 

 avoiding the surrounding vessels, the cut is directed upwards on the 

 front and mid-part of the hernia. 



Varieties of exttrnal hernia. There are two varieties of oblique TWO 

 inguinal hernia that may be mentioned (congenital and infantile), in 

 addition to the ordinary acquired type above described ; they are 

 distinguished by the condition of the peritoneal covering. 



Congenital Jti-rnia. This kind is found for the most part in the Congenital 

 infant and the child, though it may occur in the adult male. In it he 

 the tube of peritoneum (processus vaginalis^, which receives the 

 testicle in the foetus, remains unclosed and the intestine descends into how con- 

 a sac already formed for its reception. 



Infantile or encysted hernia is much rarer than congenital, and infantile 

 cannot be distinguished from the common external hernia during herma : 

 life. It was first recognised in the young child, and received its 

 name of infantile from that circumstance ; but it may be met with 

 at any period of life. 



This form of hernia occurs Avheu the fcetal processus vaginalis of how con- 

 the peritoneum is closed only in the neighbourhood of the internal s 

 abdominal ring, instead of being obliterated from that point down 

 to the testicle, so that a large serous sac will be situate in front of 

 the spermatic cord, and may occupy the inguinal canal. "With this 

 state of the peritoneum, should an external hernia with its coverings 

 descend along the cord in the usual way, it will pass behind the 

 unobliterated sac, like a viscus in a serous membrane. In this way 

 there will be two sacs, an anterior (the tunica vaginalis) containing 

 serum, and a posterior enclosing the intestine. 



An infantile hernia is first recognised during an operation by 

 D.A. u 



