DYSTOKIA DEPEXDIXG ON ANTERIOR PRESENTATION. 455 

 Lateral Deviation to the Right or Left. 



Hie lateral deviation of the head to the right or left side of the body, 

 whereby the left or right side of the neck presents at the pelvic inlet, is a 

 very serious obstacle to birth, and is only too frequently one of the most 

 difficult to be overcome. It is also one of the most frequent deviations, 

 Saake observing it in 39^ per cent, of his cases of dystokia ; and it 

 occurs far more often in the Mare than the Cow or other animals. With 

 regard to its origin, as well as to its adjustment, a wids distinction must 

 be drawn between it as it exists in the foal and other young creatures. 



The cause of lateral deviation of the head is not well ascertained in all 

 cases. It is not improbable that, in very many instances, it is due to 

 precipitate or tumultuous birth, when the os is either imperfectly or not 

 at all dilated. In such circumstances, the uterine contractions propel 

 the head of the foetus, otherwise in a good direction, towards the pelvis ; 

 but as the os is not open, and as the impelling force continues, the body 

 of the foetus pushes the nose against either the pelvis or the occluded os ; 

 this subsequently yields to one side, and then the deviation becomes in- 

 creased with every contraction. Premature rupture of the fcetal mem- 

 branes and escape of the " waters," spasm of the cervix uteri, torsion of 

 the uterus, and other anomalous conditions, may all more or less occa- 

 sion it. As with the downward deviation, if the nose is not in the axis 

 of the pelvis, or indeed of the os, even though the latter may be partially 

 dilated, misdirection may occur, and all the more rapidly should the fore- 

 limbs chance to pass into the vagina. 



The accident appears to be most frequent with primiparag. In 108 

 cases of lateral deviation of the head, Saake found 84 — or 78 per cent. 

 — in animals pregnant for the first time. The remainder were noted in 

 animals which had previously brought forth, but in which labor was pro- 

 tracted through imperfect or tardy dilatation of the os. 



This deviation is more serious when the foetus is dead than when it is 

 alive ; and when the deviation is only slight, the head fitting into the 

 concavity on the side of the neck, birth may even — though indeed rarely 

 — occur without assistance, particularly with rhe foal, which has a longer 

 and thinner head than the calf. Some authorities have remarked that 

 the deviation is more frequently to the right than the left side, and others 

 the contrary. 



In some instances there can scarcely be any doubt that the deviation 

 has taken place some time before gestation is completed, and is the 

 result of a long-continued malposition of the fcetus. In many foals, at 

 birth, the neck cannot be straightened, and the head is distorted from 

 being pressed against the neck or side of the body (Fig. 84), bones, 

 muscles, and ligaments being involved. We have referred to these in 

 describing '" Contractions " of the fcetus as a cause of dystokia. 



It is not difficult, as a rule, to distinguish the existence of lateral de- 

 viation. Usually both fore-feet are in the genital canal, but birth does 

 not progress. But an important fact to remember is that one limb — 

 that belonging to the side to which the head is bent — is shorter, or rather 

 less advanced, than the other. The hand, on being passed beyond these 

 towards the inlet, comes in contact with a rounded mass, more or less 

 occupying the whole of it, and rendering access to the uterine cavity dif- 

 ficult. Patient exploration, however, discovers this to be the bent neck ; 

 and if it be a calf, owing to the short neck, the head is soon found, and 



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