DIRECT INGUINAL HERNIA. 251 



There are three varieties of oblique inguinal hernia : common, 

 congenital, and encysted. 



Common oblique hernia is that which has been described above. 



Congenital hernia results from the nonclosure of the pouch of peri- 

 toneum 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 

 descends through it into the tunica vaginalis where it lies in contact 

 with the testicle ; so that congenital hernia has no proper sac, bat is 

 contained within the tunica vaginalis. The other coverings are the 

 same as those of common inguinal hernia. 



Encysted hernia (hernia infantilis, of Hey) is that form of pro- 

 trusion in which the pouch of peritoneum forming the tunica vagi- 

 nalis, being only partially closed, and remaining open externally to 

 the abdomen, admits of the hernia passing into the scrotum, behind 

 the tunica vaginalis. So that the surgeon in operating upon this 

 variety, requires to divide three layers of serous membrane; the first 

 and second layers being those of the tunica vaginalis ; and the third, 

 the true sac of the hernia. 



Direct inguinal hernia* has received its name from passing directly 

 through the external abdominal ring, and forcing before it the 

 opposing parietes. This portion of the wall of the abdomen is 

 strengthened by the conjoined tendon of the internal oblique and 

 transversalis muscle, which is pressed before the hernia, and forms 

 one of its investments. Its coverings are, the 



Integument, 

 Superficial fascia, 

 Intercolumnar fascia, 

 Conjoined tendon, 

 Transversalis fascia, 

 Peritoneal sac. 



Direct inguinal hernia differs from oblique in never attaining the 

 same bulk, in consequence of the resisting nature of the conjoined 

 tendon of the internal oblique and transversalis and of the transver- 

 salis fascia; in its direction, having a tendency to protrude from the 

 middle line rather than towards it. Thirdly, in making for itself a 

 new passage through the abdominal parietes, instead of following a 

 natural channel ; and fourthly, in the relation of the neck of its sac 

 to the epigastric artery ; that vessel lying to the outer side of the 

 opening of the sac of direct hernia, and to the inner side of oblique 

 hernia. 



All the forms of inguinal hernia are designated scrota/, when they 

 have descended into that cavity. 



The fascia iliaca is the tendino-fibrous investment of the psoas 

 and iliacus muscles; and, like the fascia transversalis, is thick 

 below, and becomes gradually thinner as it ascends. It is attached 

 superiorly along the edge of the psoas, to the anterior lamella of the 



* Known in America by the name ventro-inguinal hernia. G. 



