282 SURGICAL APPLIED ANATOMY. [Chap. xvi. 



the canal and consequently the obliquity of the hernia 

 are considerably reduced. Thus the axes of the two 

 forms of rupture do not present such differences as to 

 make their nature at once obvious. The direct hernia, 

 however, on reduction, will pass directly back into the 

 belly, while the indirect will, even in old cases, take a 

 slight but appreciable direction outwards. After the 

 reduction of the direct hernia, the edge of the rectus 

 muscle may be readily felt to the inner side of the aper- 

 ture, and the pulsation of the epigastric artery will 

 probably be detected on its outer side, features that 

 are both lacking in the oblique variety. From the 

 slight inducement offered to its progress, and from its 

 insignificant neck, the direct hernia is usually small 

 and globular, while for opposite reasons the oblique 

 rupture may attain large size, and tends to assume a 

 pyriform outline. 



Forms of* oblique hernia depending* upon 

 congenital delects in the " vaginal process." 

 It is well known that the testis in the foetus descends 

 from the region of the kidney into the scrotum by 

 making a way through the abdominal wall that is 

 afterwards known as the inguinal canal. 



Its descent is preceded by the passage into the 

 scrotum of a process of the peritoneum, the vaginal 

 process. The testicle usually enters the internal ring 

 about the seventh month of foetal life, and by the 

 eighth month is in the scrotum. The vaginal process 

 is often found open at birth, but it is more usually 

 found cut off from the peritoneal cavity, the portion 

 thus isolated forming the tunica vaginalis. This 

 vaginal process will have a narrowed part or neck, as 

 it passes along the inguinal canal, and will be free to 

 enlarge again on reaching the scrotum. The manner 

 in which it is cut off is as follows. It becomes oblite- 

 rated in two places, at the internal ring and at a spot 

 just above the epididyuais, the obliteration usually 



