762 



Veterinary Obstetrics 



the fetus are pushed back upon the sides of the chest so as to 

 greatly increase its transeverse diameter, while the perpendicular 

 diameter is still more profoundly increased by the rigidity of 

 the limb, and now equals the distance from the fetal withers or 

 back, to the carpus. 



The causes of this deviation may be two. When a fetus pre- 

 sents at the pelvic inlet with one or both carpal joints flexed, 

 these become impacted against the pubis, and, as the fetus con- 



FiG. 132. Complete Retention of the Anterior Limbs. 



tinues to be advanced by the expulsive efforts of the mother or 

 by traction, they tend to glide downward and finally backward 

 in a way to convert the flexed carpus into complete retention of 

 the anterior limb. 



It is quite possible that in many instances the fetus approaches 

 the pelvic inlet with the limbs extended backwards, due to an 

 arrest in their forward exten.sion. With the anterior limbs of the 

 fetus folded against the ventral surface of its body, a small 

 amount of force, applied to the lower end of the radius, pushes 

 it backward, and causes the fetus to offer at the inlet with the 

 entire forelimb retained. 



The position is not abnormal for the smaller domestic animals. 



