C. ABNORMAL PRESENTATIONS OR POSITIONS 

 OF THE FETUS. 



I. ANTERIOR PRESENTATION. 



a. Dorso-Ilial or Dorso-PuSic Positions. 



In the larger domestic animals, where the fetus normally lies en 

 arc or describes iu its attitude the segment of a circle, the ventral 

 surface concave and the dorsal convex, it is essential to the easiest 

 delivery that the fetus should be in the dorso-sacral position. The 

 body does not readily bend dorsalwards, because the inferior wall 

 of the fetus is comparatively short and inextensible and, with the 

 viscera in position, the rigidity' of the fetal body is maintained. 

 A further obstruction to its passage, in other position than the 

 dorso-sacral, is that the greater diameter of its body does not 

 correspond with the greater diameter of the pelvic canal. It is 

 possible in some cases to bring about the extraction of the fetus 

 in the dorso-ilial or dorso-pubic position, but this is chiefly in 

 those cases where the fetus is comparatively small as related to 

 the genital passages of the mother. When the fetus is so small 

 that it can be brought out in this unfavorable position, its 

 diminutive size permits the correction of the position to be made 

 with very little labor. 



The indications are usually to rotate the fetus upon its long 

 axis, and convert the dorso-ilial or dorso-pubic into the dorso- 

 sacral position. Under special conditions it may be advisable or 

 practicable to resort to forced' extraction. We have already dealt 

 with the question of rotation on page 632, and of forced extraction 

 on page 586. Both of these faihng, it may be necessary to resort 

 to embryotomy, consisting of the subcutaneous amputation of 

 one anterior limb, page 645, and evisceration, page 658, followed 

 by rotation. 



b. Deviation op the Anterior Limbs. 



The anterior limbs of the fetus are subject to greatly varying 

 deviations. While these may sometimes be unimportant in the 

 smaller species, they become of fundamental value in the larger 

 animals, such as the foal and calf. The long and rigid limbs 

 and neck of these make it essential that each extremity should 

 be fully extended in order to pass readily through the pelvic 

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