448 FCETAL DYSTOKIA. 



Lateral Deviation to the Right or Left. 



The 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 394- per cent, of his cases of dystokia ; it occurs 

 much more often in the Mare than the Covp or other animals. With 

 regard to its origin, as well as to its adjustment, a wide 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 pushes the nose against either the pelvis or the occluded os, 

 and it turns to one side ; then the deviation becomes increased with 

 every contraction. Premature rupture of the fcBtal membranes and 

 escape of the " waters," spasm of the cervix uteri, torsion of the uterus, 

 and other anomalous conditions, may all more or less occasion 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 is 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 primiparae. 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 bred, but in which labour was protracted 

 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 the 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 foetus. 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. 103) — bones, 

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

 describing " Contractions " of the foetus as a cause of dystokia. 



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

 deviation. 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 — seems to be 

 shorter, or less advanced, than the other. The hand, on being passed 

 beyond these towards the inlet, comes in contact with a convex mass, 

 more or less occupying the whole of it, and rendering access to the uterine 

 cavity difficult. Patient exploration, however, discovers this to be the 

 bent neck ; and if it be a Calf, owing to the shortness of this part, the 



