Downward Deviation of the Head 771 



There occur variations in the degree of the deviation, as in 

 other cases, but they largely arrange themselves into two groups. 

 The first group includes those of a minor character, in which, 

 when the fetus advances along the birth canal, its nose catches 

 against the pubic brim. As the fetus is pushed along, there is a 

 constant tendency for the nose to turn more and more downward 

 and backward, while the head becomes sharply flexed upon the 

 neck and the poll passes into the pelvis, to constitute what is 

 sometimes known as the poll presentation. 



From this position it has been assumed by some that the devi- 

 ation may become more and more accentuated until it reaches 

 that degree where the head passes completely downward between 

 the legs. A study of the circumstances under which the devia- 

 tion occurs tends to throw serious doubt upon this view. When 

 the limbs are advanced in the pelvic canal, they are necessaril}'^ 

 confined quite closely to each other, and it is only during the 

 early stages of advancement, before the feet have yet approached 

 the vulva, that the muzzle of the foal or calf can well drop down 

 between the two anterior feet and become jammed against the 

 pubic brim. As the two limbs advance further and further, they 

 become applied more and more closely to each other, so that it 

 would be highly improbable for the head of the fetus to pass com- 

 pletely down between them to occupy a position beneath them. 

 We hold, therefore, that the two positions are not differences of 

 degree, but are fundamentally different in origin, and that one 

 does not pass into the other by imperceptible gradations. 



The diagnosis by manual exploration is comparatively easy. 

 In the first instance the head is found lying upon the anterior 

 limbs, with the poll directed more or less upwards and forwards, 

 while the nose projects down between the limbs and is caught 

 against the pubic brim. In the second instance the head at finst 

 cannot be felt, but the limbs seem to be pushed somewhat apart 

 as they near the chest. Careful manipulation will reveal the fact 

 that the top of the neck or the mane disappears almost straight 

 downward from the top of the withers, to finally recurve back- 

 ward. By reaching around underneath the anterior limbs and 

 fetal chest, some portion of the head will most likely be reached 

 and identified. 



The handling of the downward deviation of the head offers 

 some variations according to type. 



