DVSroKIA FROM Jj:yn/:MJL POSITIONS. 457 



remarked that of the positions in the breech or posterior presentation, 

 only one is compatible with spontaneous and natural delivery — the 

 lumbosacral ; but this is only possible when the hind-limbs are fully 

 extended backwards, and are the first to enter tlie genital canal, so as 

 to gi-adually dilate the channel for the passa^'e of the voluminous and 

 rounded croup. Birth in this position, and without assistance, is more 

 frequent in the Bovine than the Equine species, and the youn<^ creature 

 is nearly always born alive. With the Mare, parturition is always 

 longer and more laborious, and the Foal quickly perishes after rupture of 

 the membranes. It therefore results that, even when the latter is in 

 the lumbo-sacral position, and everything is favourable, delivery should 

 be hastened if it is desired to preserve the life of the young creature. 



The other three posterior positions — lumbo-pubic and right and left 

 lumbo supra-cotyloidean — are unnatural, and demand the intervention 

 of the obstetrist. 



Besides, these positions, as well as the lumbo-sacral, may be compli- 

 cated by a vicious direction of the limbs or neck, which may lead to 

 as great, if less varied ditliculties, as those encountered in the anterior 

 presentation. 



A. NOKM.\L PoSTEltlOK PRESENTATION. 



We have just referred to this presentation and described what it 

 implies. 



SECTION I.— DYSTOKIA FROM ABNORMAL POSITIONS. 



As has been mentioned, these are three in number— the lumbo-picbic 

 and two lumbo-sitpra-cotyloidcaii positions. 



Lwnbo-jncbic Position. 



In this, the posterior reversed position, the foetus is lying on its back, 

 its croup and loins towards the tioor of the abdomen or the pubis of 

 the mother, with its feet and belly towards the sacrum. 



As a consequence, the hind-limbs, which soonest enter the pelvis, are 

 inclined upwards and backwards into the genital canal, and are there- 

 fore the parts that first meet the hand in exploration. Saint-Cyr points 

 OQt what might be a cause of error in this exploration, in the following 

 terms: " As the anterior face of the hoof or claws is directed upwards 

 and the plantar surface (sole) downwards, the explorer might be 

 inchned to think that it was an anterior vertehro-sacral presentation ; 

 but in pushing the exploration further, and following the cannon-bone 

 with the hand, the hock is met with — recognisable by its jlatimss on 

 each side, the point of the calcis downwards, the hend being upwards in 

 the same direction as the wall of the hoof ; whereas the bend of the 

 knee is in the same direction as the sole of the foot. Beyond the hock 

 the hand also comes in contact with the croup and the tail, lying 

 towards the maternal pubis." 



The obstacle to birth lies chiefly in the thighs and buttocks, while 

 the hind-feet project against the mother's sacrum, and, in addition to 

 increasing the resistance, threaten to lacerate the organs interposed 

 between them — the vagina or rectum, or both — and that bony mass. 

 Besides this, the body of the fcetus itself forms a curve exactly the 



