426 DISSECTION OF THE ABDOMEN. 



should cut on the front and mid-part of the tumor, so as to avoid the epi- 

 gastric vessels, whose lateral position cannot be known. 



Variety of internal hernia. Another kind of internal hernia (superior) 

 occurs through that part of the area of the triangular space which is ex- 

 ternal to the conjoined tendon. Its existence is determined by the unusual 

 position of the obliterated hypogastric artery inside the abdominal wall 

 (p. 427). 



The intestine protrudes through the wall of the abdomen close to the 

 epigastric artery, and descends along nearly the whole of the inguinal 

 canal to reach the external abdominal ring ; so that the term " direct" 

 would not apply strictly to this form of internal hernia. 



Coverings. As the gut traverses nearly the whole of the inguinal 

 canal, it has exactly the same coverings as the external hernia, viz., the 

 skin and the superficial fascia, the spermatic and cremasteric fascias, the 

 fascia transversalis, and the subperitoneal fat and the peritoneum. 



Diagnosis. This form of internal hernia would be considered external 

 during life from its course and its form ; and yet it must be remembered 

 that the epigastric vessels are placed on the outer part of its neck, whilst 

 in the hernia which it stimulates, they lie on the inner side, Its nature 

 can be ascertained with certainty only after death. 



Seat of stricture. The constriction of the intestine will take place 

 from similar causes, and at the same spots as in the external hernia. 



Division of the stricture. From an inability to decide always in the 

 living body whether a small hernia is internal or external, the rule ob- 

 served in dividing the stricture of the neck of the sac is, to cut down upon 

 the mid-part of the tumor; and if it is necessary to open the peritoneum, 

 to cut directly upwards, as in the other kinds of inguinal hernia. 



UMBILICAL HERNIA, or exomphalos, is a protrusion of the intestine 

 through or by the side of the umbilicus. It is very variable in size, and 

 its course is straight through the abdominal wall. 



Coverings. The coverings of the intestine are few in number : They 

 are the skin and the superficial fascia ; a prolongation from the tendinous 

 margin of the umbilical opening ; together with coverings of the fascia 

 transversalis, the subperitoneal fat, and the peritoneum. Over the end of 

 the tumor the superficial fascia blends with the other contiguous struc- 

 tures, and its fat disappears. 



If the hernia is suddenly produced, it may want the investment other- 

 wise derived from the edge of the umbilicus. 



Seat of stricture. The stricture on the intestine is generally at the 

 margin of the tendinous opening in the abdominal wall ; and it may be 

 either outside, or in the neck of the sac, as in the other kinds of hernia. 

 It should be remembered that the narrowed neck is at the upper part and 

 not in the centre of the swelling. 



Division of the stricture. The constriction may be removed by cutting 

 externally the parts around the neck. Or if the sac is to be opened, the 

 knife may be carried upwards in cutting through the stricture ; but there 

 is not any vessel liable to injury in the operation. 



OTHER FORMS OF HERNIA. At each of the other apertures in the 

 parietes of the abdomen, a piece of intestine may be protruded, so as to 

 form a hernial tumor. For instance there may be femoral hernia below 

 Poupart's ligament, with the femoral vessels ; obturator hernia through 

 the thyroid foramen, with the artery of the same name; and ischiatic 

 hernia through the ischiatic notch. 



