92 BOVINJK OBSTETBICS 



Anteriorly it is held by the vaginal portion of tlio 

 uterus and is there held in position by the cervix uteri. 

 The superior wall consists of mucosa, muscularis and, partly, 

 adventitia. At the abdominal cavity the adventitia is replaced 

 by a serous membrane — that is, the peritoneum as part of the 

 xecto-vaginal excavation. The inferior wall, up to the angle 

 formed by it and the urethra, is also covered by a serous layer. 

 The urethra in the cow is held in place by the very strong 

 pubo-vesical ligament, composed of strong elastic fibrous 

 fibres. This ligament also indirectly fixes the inferior vaginal 

 wall. The upper and lateral walls of the vagina, therefore, are 

 more easily displaced than the lower one. 



JEtiology. — The causes inducing this inversion are partly 

 predisposing, partly direct. As an occasional cause, we must 

 mention relaxation of those organs which fix the vagina, as the 

 deep perineal fascia, perineal muscles, the broad pelvic liga- 

 ments and mesometrium. This relaxation occurs frequently at 

 the end of gestation, when the pelvic tissues become infiltrated 

 in consequence of increased blood pressure. Predisposed 

 cows are lymphatic animals which gave a great deal of milk 

 while pregnant, and emaciated ones. Experience teaches that 

 cows advanced in gestation easily get a prolapsus, when sub- 

 jected to long drives and railroad travel. Prolapsus vaginae is 

 also caused by standing cows on floors inclined too much to the 

 rear. It is generally known that when the posterior extremi- 

 ties of the animal during gestation are kept lower behind than 

 in fiont, inversion of the vagina often occurs. The continuous 

 pressure exerted upon the superior wall of the vagina, the 

 abdominal viscera in such a position forces it to turn its con- 

 cave side toward the abdominal cavity. The gravid uterus 

 also presses upon the superior vaginal walls, pushing this one 

 backwards. The greater this pressure, especially toward the 

 end of gestation, the more is the vagina displaced toward the 

 vulva. Thia factor already belongs to the domain of direct 

 causes. When the intestines enter the recto-vaginal excava- 

 tion, — always the case in this sloping position of the hind- 

 quarters, — the uterus also becomes displaced. The weight of 



