.610 ACCIDENTS AFTER PARTURITION. 



rupture has been already fully alluded to at p. 194, and we have now to 

 study its occurrence during and after birth. 



Bujjture during Birth. — Eupture of the uterus may occur spon- 

 taneously in a complete or incomplete form during parturition ; and 

 though the accident is perhaps not so frequent in animals as in woman, 

 yet there are many cases on record in which it has undoubtedly occurred 

 in them, and it has been affirmed by highly competent authorities that 

 it has been observed in Cows which had not received any assistance 

 during parturition. 



It can easily be understood why, if there is any material obstacle to 

 the passage of the foetus — such as induration or torsion of the cervix, 

 or malposition or deformity of the young creature — the violent con- 

 tractions of the powerful muscular layer of the organ should overcome 

 the resistance of some portion of its own fibres, and thus lead to a more 

 or less extensive laceration, which may involve the other tunics and 

 produce complete perforation. Non-perforating or incomplete lacera- 

 tions occur, in the majority of instances, towards the cervix, and are 

 usually longitudinal. Complete rupture may take place at any part of 

 the organ. 



This accident is more likely to occur spontaneously when there 

 happens to be an alteration in the texture, wholly or partially, of the 

 uterine wall ; though this predisposing cause does not appear to be so 

 often present in animals as in the human female, in which sudden per- 

 forating ruptures never take place when the organ is healthy. Never- 

 theless, there can be no reason to doubt that in animals alterations in 

 the tissue of this organ may and do occur ; and, as in woman, this may 

 assume the form of anomalous development ; interruption of the normal 

 tissue by interstitial fibroids or cicatrices ; separation of the muscular 

 fibres by submucous fibroids, or by projecting thin parts of the foetus ; 

 inflammatory softening of some portions of the parenchyma during 

 pregnancy ; or thinning of the wall at some part by pressui-e. This 

 pressure may arise from contact with the brim of the pelvis, or exostoses 

 in or upon the bony canal. 



The exciting cause, however, proceeds from considerable impediment 

 to the progress of labour, and the accident is due to the energetic con- 

 tractions of the uterine walls and abdominal muscles, as well as to the 

 pressure, direct or indirect, of the diaphragm by the fully dilated chest. 



In such cases the rent may be so great that the foetus passes entirely 

 through it into the abdominal cavity, enveloped or not in its membranes ; 

 or only a portion of it escapes through the tear, and it ma}' be extracted 

 therefrom with more or less difficulty per vias nahirales ; in some 

 recorded cases birth has taken place by natural efforts, the existence of 

 rupture only becoming evident when the uterus was accidentally extruded 

 after birth. 



More frequently, however, the accident arises from artificial mechanical 

 causes, brought into operation in the course of manoeuvres for effecting 

 the extraction of the foetus. The various instruments employed may 

 either tear or incise the uterus ; or the organ may be lacerated during 

 traction on the foetus when the " waters " have escaped, and its walls 

 closely envelop the young creature ; or during retropulsion or version. 

 The thinness of the uterine wall at this period renders such an accident 

 as laceration one of easy occurrence ; and, however large the tear may 

 be during life, after death it usually appears much smaller, because of 

 the contraction of the muscular tissue. 



