DISPLACEMENT OF THE PREGNANT UTERUS 153 



abdominal cavity, but its dimensions vary. Many investigators 

 are of the opinion that excessive distention of the rumen, as 

 observed in tympanites, may induce the rotation. Experience 

 at the same time teaches that tympanites may exist without 

 causing a torsio uteri in such an animal. Torsio uteri, as 

 already stated, may occur at different periods of pregnancy. 

 The causes are as yet quite obscure, although they probably 

 depend on the same factor which produces torsion at a later 

 period, viz., active movements of the foetus. 



From an obstetrical point of view, torsion originating 

 immediately before parturition is of most interest. The active 

 movements of the calf toward the termination of pregnancy 

 may produce changes in the position of the uterus on account 

 of the lessened amount of foetal water, especially when the calf 

 can brace against the rumen or that part where the rectus 

 abdominis muscle is attached beneath the pubis (Mosching). 



The conditions for the production of a torsio uteri are still 

 more favorable when the cervix uteri has begun to dilate. At 

 that time the uterus has contracted a little and is moulded on 

 the calf. Most cases of torsio uteri therefore occur at that 

 time, proven by the fact that in many cases found in the litera- 

 ture the OS uteri was dilated after correction of the malposition, 

 and occasionally a living calf was born. 



It appears to happen once in a while that torsion occurs 

 when the os uteri is closed, and after correcting the faulty state 

 of the uterus, the hand cannot be introduced. Torsion may 

 then produce circulatory disturbances, which produce uterine 

 contractions — that is, labor pains. On removal of the spiral 

 twist, pains cease at once or continue and effect dilatation of 

 the cervix and parturition. 



The origin of a torsion is to be confined in most eases to 

 that time when the first pains occur. It is not reasonable that 

 a rotation could exist for days or weeks and a live calf be born 

 on correcting of such a state. Under such conditions there must 

 be circulatory disturbances which endanger the life of the 

 foetus and produce pains, or a torsion of long standing would 

 lead to such changes that a reposition becomes impossible. 



