68o A MANUAL OF ANATOMY 



sac of the hernia, and this form is therefore spoken of as a hernia into 

 the tunica vaginalis. In such cases the bowel more or less completely 

 envelops the testis. (2) The processus vaginalis may be shut off only 

 just above the testis, the part above this remaining as a funicular process 

 communicating above with the general peritoneal cavity. In such cases the 

 bowel descends into the funicular process, which thus forms the sac of the 

 hernia. This form is therefore spoken of as a hernia into the funicular 

 process. 



Infantile Hernia.— There are two forms of infantile hernia, infantile hernia 

 proper and encysted hernia. In both there is a funicular process which 

 is closed above, towards the internal abdominal ring. It may also be closed 

 below just above the testis, being thus distinct from the tunica vaginalis, 

 or it may simply be an upward extension of the tunica vaginalis. In either 

 case it is situated in front of the spermatic cord. In infantile hernia proper 

 the bowel, having elongated the parietal peritoneum to form a sac, descends 

 between the spermatic cord and the funicular process. Its importance con- 

 sists in the fact that, before the bowel can be exposed in operating, three 

 serous layers must be divided, two of these belonging to the funicular process 

 and the other representing the wall of the hernial sac. In this form the 

 descent of the bowel is arrested at the upper part of the testis. In encysted 

 hernia the bowel, having elongated the parietal peritoneum to form a sac, 

 pushes against the upper part of the funicular process so as to invaginate it in 

 a downward direction in the form of a cup, in which the bowel, enclosed 

 in its sac, lies. The condition of matters is therefore very much like an egg 

 set in its cup, assuming that the top of the shell is removed, and that the wall 

 of the cup is formed of two layers. To bring out this simile, the contents of 

 the egg may be taken as representing the bowel, the shell of the egg being the 

 sac of the hernia, and the assumed two layers of the wall of the cup repre- 

 senting the two serous layers of the doubled down or invaginated funicular 

 process, the cavity thus formed representing the inside of the cup. In this 

 form, as in infantile hernia proper, three serous layers must be divided 

 before the bowel is exposed in operating, two of these belonging to the 

 invaginated funicular process and the other representing the wall of the 

 hernial sac. 



Umbilical Hernia (Exomphalos). — By an umbilical hernia is meant a pro- 

 trusion of bowel or of great omentum from the abdominal cavity through the 

 umbilicus. The protrusion occurs through the upper part of the umbilicus, 

 which, containing only the obliterated umbilical vein, is weaker than the lower 

 part where the obliterated hypogastric arteries and the urachus lie. The 

 coverings of an umbilical hernia are as follows : 



1. Parietal peritoneum. 



2. Subperitoneal fat or areolar tissue. 



3. Fascia transversalis. 



4. An expansion from the decussating fibres of the aponeuroses of the 

 abdominal muscles of opposite sides. 



5. Superficial fascia. 



6. The cicatricial cutaneous umbilical tissue. 



There is no vessel liable to be injured in operating on this form of hernia, 

 the deep epigastric artery being about i^ inches from the linea alba. 



The congenital form of umbilical hernia consists in a protrusion of bowel 

 or omentum through the centre of the umbilicus into the umbilical cord, in 

 which it may descend for some distance. Its possible presence will show the 

 propriety of carefully examining the cord before ligaturing it after birth. 



The anterior abdominal wall above the umbilicus presents pos^ 

 teriorly a median fold of parietal peritoneum, which represents a 

 part of the upper border of the falciform ligament of the liver. 

 This fold contains a portion of the obliterated umbilical vein, 

 which is now spoken of as the round ligament of the liver. It 

 extends upwards from the umbilicus to the interlobar or umbilical 



