424 ABDOMEN 



however, other forms of inguinal hernia which do not pass through the 

 abdominal inguinal ring but through the posterior wall of the canal to the 

 medial side of the inferior epigastric artery, and between it and the obliterated 

 part of the umbilical artery, or still more medially between the obliterated 

 part of the umbilical artery and the lateral border of the rectus. Such 

 hernire, because they do not pass obliquely along the inguinal canal but 

 more directly through its posterior wall, are called by the surgeon direct 

 inguinal hernire. As there are no congenital diverticula of the peritoneum 

 in these regions such hernias must be due either to the slow distension of 

 weak points in the posterior wall of the inguinal canal, under the influence 

 of the intra-abdominal pressure, or to the instant rupture of such points when 

 the pressure is suddenly increased. After a pouch of the posterior wall, 

 containing gut, has been protruded into the canal, or after a portion of the 

 peritoneal sac containing gut has been forced through the posterior wall 

 into the canal, the action of the abdominal pressure will tend to force the 

 protrusion along the line of least resistance, which is usually down the canal 

 to the subcutaneous inguinal ring. The coverings of the direct hernia will 

 differ according to whether the hernia has torn the posterior wall or forced 

 it forwards as a covering, and, in the latter case, according to whether the 

 hernia has passed from the medial inguinal pouch between the inferior 

 epigastric artery and the obliterated part of the umbilical artery, or 

 through the supravesical pouch to the medial side of the obliterated artery. 

 The coverings of the hernia passing from the medial inguinal pouch will be 

 the same as those of the oblique hernia, except that transversalis fascia will 

 take the place of infundibuliform fascia ; but if the hernia passes from the 

 supravesical pouch, to the medial side of the obliterated part of the um- 

 bilical artery, it will push before it the falx inguinalis, it will enter the canal 

 below the upper border of the cremasteric fascia, and it will receive no 

 sheath from the latter fascia, from within outwards, therefore its anatomical 

 coverings will be (i) peritoneum, (2) extra-peritoneal fat, (3) transversalis 

 fascia, (4) falx inguinalis, (5) intercrural fascia, (6) superficial fascia, 

 (7) skin. The student should also understand that whilst it is commonly 

 believed that oblique herniae are usually due to the persistence of a portion 

 of the processus vaginalis there is no anatomical reason why a new peritoneal 

 sac should not be formed in the region of the lateral inguinal fossa, that is 

 in the region of the abdominal inguinal ring, as easily as in other regions. 

 If such a pouch were formed it would pass along the line of the canal, its 

 coverings would be similar to those of a hernia which had passed into the 

 upper persisting part of the processus vaginalis, and its relationship to the 

 tunica vaginalis would depend largely upon the size of the latter sac, that is 

 upon how much of the lower part of the original processus remained un- 

 obliterated, and upon the more anterior or posterior position of the upper 

 end of the tunica vaginalis. 



Femoral Hernia. This consists in the protrusion of some abdominal 

 contents from the abdominal cavity into the region of the thigh. In its 

 descent it passes behind the inguinal ligament along the femoral canal of 

 the femoral sheath. It is consequently mainly the duty of the student 

 who is engaged in the dissection of the lower limb, and within whose 

 domain the femoral sheath lies, to investigate the anatomical connections 

 of this variety of hernia (p. 185). Still it is essential that the dissector of 

 the abdomen should examine, from its abdominal aspect, the femoral ring 

 or aperture of communication between the femoral canal and the abdominal 

 cavity, and give the dissector of the lower limb an opportunity of doing 

 so likewise. 



The femoral ring is placed immediately below the inguinal ligament, 

 in the interval between the external iliac vein and the base of the lacunar 



