764 SURGICAL ANATOMY OF INGUINAL HERNIA. 



adipose tissue. Opposite the internal ring it is continued round the surface of 

 the cord, forming for it a loose sheath. 



The epigastric artery bears a very important relation to the internal abdominal 

 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 variable 

 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 continuous with the peritoneum by 

 an opening at its upper part. 



INGUINAL HERNIA. 



Inguinal Hernia includes that form of protrusion which makes its way through 

 the abdomen in the inguinal region. 



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

 internal or direct. 



External or oblique inguinal hernia, the most frequent of the two, is that form 

 of protrusion which 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 liernia is that form of protrusion which 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 infundibuliform process of the transversalis 

 fascia. In passing along the inguinal canal, it displaces upwards 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 inter- 

 columnar fascia. Lastly, it descends into the scrotum, receiving coverings from 

 the superficial fascia and the integument. 



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

 external ring, are, from without inwards, the integument, superficial fascia, inter- 

 columnar fascia, Cremaster muscle, transversalis 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 adhesions of the cover- 

 ings 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 Transversalis, 



