828 SURGICAL ANATOMY OF INGUINAL HERNIA. 



The epigastric artery bears a very important relation to the internal abdomi- 

 nal ring. This vessel lies between the transversalis fascia and peritoneum, and 

 passes obliquely upwards and inwards, from its origin from the external iliac, 

 to the margin of the sheath of the Rectus muscle. In this course, it lies along 

 the lower and inner margin of the internal ring, and beneath the commencement 

 of the spermatic cord, the vas deferens curving round it as it passes from the 

 ring into the pelvis. 



The peritoneum, corresponding to the inner surface of the internal ring, pre- 

 sents a well-marked depression, the depth of which varies in different subjects. 

 A thin fibrous band is continued from it along the front of the cord, for a vari- 

 able distance, and becomes ultimately lost. This is the remains of the pouch 

 of peritoneum which, in the foetus, accompanies the cord and testis into the 

 scrotum, the obliteration of which commences soon after birth. In some cases, 

 the fibrous band can only be traced a short distance ; but occasionally, it may 

 be followed, as a fine cord, as far as the upper end of the tunica vaginalis. 

 Sometimes the tube of peritoneum is only closed at intervals, and presents a 

 sacculated appearance; or a single pouch may extend along the whole length 

 of the cord, which may be closed above ; or the pouch may be directly con- 

 tinuous with the peritoneum by an opening at its upper part. 



There are two principal varieties of inguinal hernia: external or oblique, 

 and internal or direct. 



External or oblique inguinal hernia, the more frequent of the two, takes the 

 same course as the spermatic cord. It is called external, from the neck of the 

 sac being on the outer or iliac side of the epigastric artery. 



Internal, or direct inguinal hernia, does not follow the same course as the 

 cord, but protrudes through the abdominal wall on the inner or pubic side of 

 the epigastric artery. 



OBLIQUE INGUINAL HERNIA. 



In Oblique Inguinal Hernia, the intestine escapes from the abdominal cavity 

 at the internal ring, pushing before it a pouch of peritoneum, which forms the 

 hernial sac. As it enters the inguinal canal, it receives an investment from 

 the subserous areolar tissue, and is inclosed in the irifundibuliform process of 

 the transversalis fascia. In passing along the inguinal canal, it displaces up- 

 wards the arched fibres of the Transversalis and Internal Oblique muscles, and 

 is surrounded by the fibres of the Cremaster. It then passes along the front of 

 the cord, and escapes from the inguinal canal at the external ring, receiving an 

 investment from the intercolumnar fascia. Lastly, it descends into the scrotum, 

 receiving coverings from the superficial fascia and the integument. 



The coverings of this form of hernia, after it has passed through the external 

 ring, are, from without inwards, the integument, superficial fascia, intercolum- 

 nar fascia, Cremaster muscle, infundibuliform fascia, subserous cellular tissue, 

 and peritoneum. 



This form of hernia lies in front of the vessels of the spermatic cord, and 

 seldom extends below the testis, on account of the intimate adhesion of the 

 coverings of the cord to the tunica vaginalis. 



The seat of stricture in oblique inguinal hernia is either at the external ring, 

 in the inguinal canal, caused by the fibres of the Internal Oblique or Transver- 

 salis or at the internal ring, more frequently in the latter situation. If it is 

 situated at the external ring, the division of a few fibres at one point of its cir- 

 cumference, is all that is necessary for the replacement of the hernia. If in the 

 inguinal canal, or at the internal ring, it will be necessary to divide the aponeu- 

 rosis of the External Oblique so as to lay open the inguinal canal. In dividing 

 the stricture, the direction of the incision should be directly upwards. 



When the intestine passes along the spermatic canal, and escapes from the 

 external ring into the scrotum, it is called complete oblige inguinal, or scrotal 



