Scrotal Hernia. Inguinal Hernia 1059 



2. Scrotal Hernia. Inguinal Hernia. 



Scrotal or inguinal hernia may exist in any new-born domes- 

 tic animal, perhaps most frequently in the foal and pig, rarely in 

 ruminants and carnivora. Inguinal hernia is virtually a defect 

 of the male, though very rarely it exists in the female. As shovsm 

 in Fig. 57, page 338, there exists, early in fetal life, the internal 

 inguinal or abdominal ring, through which passes the guberna- 

 culum testis from the scrotum to the testicle. I^ater, as the male 

 animal develops, there occurs an evagination of the peritoneum, 

 the processus vaginalis, through the inguinal ring into the scrotal 

 pouch, and the testicle ultimately descends, until finally theevagi- 

 nated portion of the peritoneum forms the external or parietal 

 layer of the scrotal peritoneum. 



As already related on page 336, the descent of the testicle 

 occurs at a variable period of time, controlled largely by species. 

 In solipeds and ruminants, as well as in swine, the glands are 

 usually in the scrotum at the time of the birth of the young 

 animal. In some cases the inguinal ring in the fetus is abnor- 

 mally large, and the intra- abominal pressure during early fetal 

 life may cause portions of the viscera to be forced out through 

 the ring, and, remaining there, prevent the latter from normally 

 closing, or narrowing to such a degree as to prevent the escape of 

 viscera from the abdominal cavity. In all domestic animals, the 

 inguinal ring normally remains pervious throughout life, and 

 consequently inguinal hernia does not depend upon the abnormal 

 existence of an opening, but merely upon its abnormal size. 



In new-born foals, especially among the draft breeds, scrotal 

 hernia is very common at birth, but is usually of a temporai-y 

 character, and spontaneously disappears. However, this does 

 not always occur, and in some instances the internal inguinal 

 ring is excessively large, so that portions of viscera protrude 

 through it, which, by their weight, tend to render the abnormal 

 dilation of the ring permanent and to cause the hernia to persist 

 throughout the life of the animal unless surgically handled. In 

 the pig, scrotal hernia is quite common, and usually tends to re- 

 main permanent unless surgical interference takes place. 



The size of the hernial ring shows every possible variation. 

 We have observed, in the foal, an internal ring four or five inches 

 in diameter, through which virtually all the abdominal viscera. 



