APPENDIX 



Equine Umbilical Hernia 



This affection occurs in all animals and with respect 

 to numhers affected, subjects of the equine species 

 rank first innong- our patients. The nature of this 

 I'oT'ni of hernia is such that veterinarians ai'c fre- 

 ([uently asked to treat these cases during the castrat- 

 ing season. Causes of umbilical hernia may be con- 

 sidered under two classifications, congenital and occa- 

 sional or traumatic. Since the proportion of cases that 

 are not congenital is insignificant, the occasional cases 

 -vvill receive no further consideration here. 



During intra-uterine life, as soon as the visceral 

 organs have attained considerable size, there is not 

 sufficient room within the splanchnic cavity for all of 

 the viscera. Accommodation of this normally splanch- 

 nectopic mass is afforded l)y the umbilical cord until 

 growth of the abdominal cavity favors a return of the 

 viscera and contraction of the abdominal walls around 

 the umbilicus takes place. In some cases, for reasons 

 not definitely known, there is failure of complete clos- 

 ure of the abdominal walls around the ring, and the 

 result is hernia. Rupture of the umbilical cord usually 

 takes place at its weakest and most constricted part, 

 which, in foals, is about an inch and a half from the 

 body. With rupture of the cord there occurs marked 

 retraction of the ends of the umbilical arteries and 

 some retraction of veins and constriction of the stump 



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