290 



DISSECTION OF THE ABDOMEN. 



Internal 

 hernia. 



Triangle of 

 Hesselbach : 

 boundaries ; 



constituents 

 of wall ; 



and disposi- 

 tion of 

 muscles. 



Hernia in 

 this space of 

 two kinds. 



Coverings 

 of the more 

 common 

 kind are 



peritoneum 

 and subja- 

 cent tissue, 

 transver- 

 sal! s fascia, 

 conjoined 

 tendon, 



spermatic 

 fascia, 

 superficial 

 fascia, and 

 skin. 



the knife opening the tunica vaginalis before the sac of the 

 hernia. 



INTERNAL or DIRECT INGUINAL HERNIA escapes on the inner 

 side of the deep epigastric artery, and has a straight course through 

 the abdominal parietes. Its situation and coverings, and the seat of 

 stricture, will be understood after the examination of the part of the 

 abdominal wall through which it passes. 



ANATOMY OF INTERNAL HERNIA. In the abdominal wall near the 

 pubis is a triangular space to which the name of Hesselbactis trinmji'- 

 has been given. This is bounded by the deep epigastric artery ex- 

 ternally, the outer edge of the rectos muscle internally, and the inner 

 part of Poupart's ligament below ; it measures about two inches 

 from above down, and one inch and a half across at the base. 



The constituents of the abdominal wall in this area are the 

 integuments, the muscular strata, and the layers lining the interior 

 of the abdomen, viz., transversalis fascia, subperitoneal tissue, and 

 peritoneum. The muscles have the following arrangement : The 

 aponeurosis of the external oblique is pierced by the external 

 abdominal ring, towards the lower and inner angle of the space. 

 The internal oblique and transversalis, which come next, are united 

 together in the conjoined tendon ; and as this descends to its inser- 

 tion into the pectineal line it covers the inner two-thirds (about an 

 inch) of the space, and leaves uncovered about half an inch between 

 its outer edge and the epigastric vessels, where the transversalis 

 fascia appears. 



Any intestine protruding in this spot must make a new path for 

 itself, and elongate the different structures, since there is not any 

 passage by which it can descend, like an external hernia. Further, 

 the coverings of the hernia, and its extent and direction in the 

 abdominal wall, must vary according as the gut projects through the 

 portion of the space covered by the conjoined tendon, or through 

 the part external to that tendon. 



Course and coverings of the hernia. The commoner kind of in- 

 ternal hernia passes through the part of the triangular space which 

 is covered by the conjoined tendon. 



The intestine in protruding carries before it the peritoneum, the 

 subperitoneal fatty membrane, and the transversalis fascia ; next it 

 elongates the conjoined tendon, or, in the case of a sudden rupture, 

 separates the fibres and escapes between them. It then advances 

 into the lower part of the inguinal canal, opposite the external 

 abdominal ring, and passes through that opening on the inner side 

 of the cord, receiving at the same time the covering of the spermatic 

 fascia. Lastly, it is invested by the superficial fascia and the skin. 



In number the coverings of an internal hernia are the same as 

 those of an external ; and in kind the only differences are that the 

 covering of transversalis fascia is not furnished by the infundibuli- 

 form process, and the conjoined tendon is substituted for the cremas- 

 teric fascia. 



The position of the openings in the abdominal wall, and the 



