III. TRANSVERSE PRESENTATIONS. 



a. Dorsal Transverse Presentation. 



Transverse presentations are virtually confined to the unipa- 

 rous animals, and among these the overwhelming majority occur 

 in the mare. The fetus usually presents ventrally, except in 

 those cases we have already described as Bi-cornual Pregnancy 

 on page 716. 



When the dorsum of the fetus offers at the pelvic inlet in the 

 right or left cephalo-ilial position, the position is usually uncom- 

 plicated by any further deviation, so that, when the operator 

 inserts his hand, it comes at once into contact with the dorsal 

 surface of the fetus, which is easily recognized. By extending 

 the hand to the right or left, he may palpate and recognize the 

 hips or the shoulders and neck. As a general rule the operator 

 does not come in contact with the head or any of the feet, but 

 only with the body, although in rare cases one or more of the 

 feet may be more or less misplaced in their general relation to 

 the body of the fetus, and project in such a manner that they 

 may be felt or grasped by the operator. In one case in our ex- 

 perience, one hind leg passed backward over the fetus into the 

 pelvic canal. 



The causes of transverse presentations are not well defined. 

 Most obstetrists hold that they are acquired positions, occurring 

 during labor ; but, as we have related, page 716, the fetus of the 

 mare occasionally develops equally in the two uterine cornua, in 

 a transverse position. In the anomalous development which we 

 have described, the fetal body revolves upon its long axis in order 

 to attain a stable position. 



We do not know that all fetuses developing transversely in 

 the mare undergo this rotation, and we can readily conceive it as 

 being wholly possible that no rotation should occur, in many 

 cases, and consequently that the fetus may develop transversely 

 and, without rotation, present transversely at the time of partu- 

 rition. 



Handling. Version, as described on page 634, is usually 

 the best and most effective method of handling. In almost every 

 case it succeeds well. Should this fail, it may be necessary to 

 perform detruncation in the lumbar region. The detruncation 

 is to be accomplished chiefly with the chisel, severing first the 

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