INGUINAL HERNIA. 393 



following up the inner border of the adductor longus tendon, 

 made tense by abduction of the slightly flexed thigh. 



A hernia which emerges from the inguinal canal is spoken of 

 as a complete inguinal hernia. It is usual to give a somewhat 

 elaborate description of the coverings of such a protrusion, 

 but it is difficult, and of little practical importance, to make 

 out these layers separately. In cutting down upon a hernial 

 sac what is really desirable is to be able to distinguish the sac 

 itself, rather than to differentiate the different layers which 

 cover it. 



In the older operative procedures, with the incision made 

 through the scrotum, the skin is the first layer, and then follows 

 the dartos tissue, then the layer derived from the deep portion 

 of the superficial fascia, covering the superficial abdominal ring 

 itself and called the intercolumnar fascia, after which the 

 cremasteric fascia and muscle will be exposed, then the infundi- 

 buliform fascia derived from the fascia transversalis, beneath 

 which is a somewhat fatty layer composed of extraperitoneal 

 tissue covering the sac itself. 



In the present-day method of exposing the hernial sac by an 

 incision parallel with the inner half of Poupart's ligament and a 

 finger's breadth above it, the following structures will be divided 

 before the sac is laid bare : The skin, two layers of superficial 

 fascia (in which some small blood vessels may be cut), the 

 aponeurosis of the external oblique, and, when this is cut, 

 the interior of the canal will be exposed, and lying within it 

 the ilio-inguinal nerve running down upon the neck of the sac, 

 which itself is covered by the cremasteric and infundibuliform 

 fasciae, the spermatic cord being placed in the great majority of 

 cases posterior to the sac. 



The sac may be recognised chiefly by its colour, which is in 

 most instances a characteristic slaty-blue when strangulation is 

 present, and of a bluish-white opaque look in non-strangulated 

 cases. Sometimes typical arborescent vessels may be observed 

 on its outer aspect, and it is important to recollect that the 

 external surface of the sac is rough, and that it is not until 



