PRACTICAL CONSIDERATIONS: ABDOMINAL HERNIA. i775 



It should be noted that in this form of hernia the density of the aponeuroses 

 that bound the femoral ring and the upper edge of the saphenous opening adds to the 

 evil effects of constriction of the hernia, which are also intensified by the congestion 

 of its contents due to the sharp angle made by the sac as it presses forward upon the 

 thigh. The constriction may be due to pressure against Hey's ligament (page 636 ), 

 Poupart's ligament, or Gimbernat's ligament. The relations of the neck of the sac to 

 the obturator artery (page 814 ), which once in three and a half cases arises from the 

 epigastric and in two-fifths of such cases passes across the femoral ring (Fig. 1498 ) 

 or close to its inner border, should be recalled in performing herniotomy. About a 

 half-inch above and to the outer side of the ring lie the deep epigastric vessels ; the 

 femoral vein lies externally ; beneath the ring the pectineus fibres covering the bone 

 are often so thin that not enough room can be obtained by incision, which is therefore 

 made upward and a little inward, and preferably with a blunted knife that may divide 

 the tense aponeurosis without damage to the vessels which, when they are present, 

 lie in loose cellular tissue a twelfth to a sixth of an inch from the edge of the ring. 



Fig. 1498. 



Anterior superior iliac spine - 



Iliacus muscle- 

 Deep circumflex iliac artery 



/Artery 

 External iliac < 



I Vein 



Obturator nerv 



Poupart's ligament 

 Transversalis muscle 



Rectus muscle 



Deep epigastric vessels 



Femoral ring 



Gimbernat's ligament 



bturator artery from deep 

 epigastric 



Round ligament 



Obturator canal^''^ 

 Pubic branch of obturator artery. 



l_Symphysis 



Dissection of part of left half of pelvis and adjacent body-wall, showing obturator artery arising from deep 



epigastric and crossing femoral ring. 



Umbilical hernia is most conveniently divided from either a clinical or an 

 anatomical stand-point into the congenital and the acqziired forms. A congenital um- 

 bilical hernia {hernia funiculi 2imbilicalis) is the result of a defect of development, 

 the anterior abdominal wall failing to close in the region of the navel. Analogous 

 malformations — harelip, spina bifida, vesical exstrophy — sometimes coexist. In addi- 

 tion to intestine, other abdominal viscera may be found in the hernial contents ; and 

 in marked cases the condition resembles an eventration (fissura abdominalis) rather 

 than a hernia. Indeed, in some of its forms, the congenital variety is not a true 

 hernia, for ' ' we are not concerned with viscera escaped from a cavity, but with viscera 

 which have never entered it" ( Malgaigne ) . 



In the lesser cases the gut — possibly Meckel's diverticulum {g.v.) — protrudes 

 into the substance of the cord, separating the structures (page 53) and covered by 

 a layer of embryonic tissue (the jelly of Wharton) and by the amniotic tissue con- 

 tinuous with the skin. A thin avascular membrane directly continuous with the 

 parietal peritoneum is sometimes present. These layers are rarely separately demon- 

 strable, and are often so thin as to be transparent. 



In the cases in which only a very small knuckle of gut or a diverticulum is 

 involved (hernia at the root of the cord) there may be merely thickening or enlarge- 



