PRESENTATIONS OF THE PELVIS. 325 



than things. In fact, if those accoucheurs who reject the third po- 

 sition of the feet, admit under that title only those cases where the 

 middle line of the child's back glides along behind the symphysis pubis 

 to the very close of labor, they are no doubt partly right, and such 

 a labor must be extremely rare; but if, on the contrary, in order 

 to constitute such a case, it suffices for the child to descend in this 

 way until the arrival of the head only, we are not permitted to be 

 ignorant not merely of its possibility, but also of its very great 

 frequency. 



During the progress of the labor, then, this third position almost 

 always converts itself, a little sooner or later, into the first or second; 

 sometimes it lasts only until the arrival of the hips at the superior 

 strait; sometimes it maintains itself until the shoulders engage; 

 sometimes it is not converted into a diagonal position until the breast 

 has descended quite into the excavation; finally, it may happen that 

 it does not become converted at all, and then one of two things is 

 observed to take place: either the hips, the shoulders, and the head 

 do not turn upon their axes at the abdominal strait, in the excava- 

 tion, nor at the inferior strait, and the child's back continues to look 

 to the front of the mother both out of the pelvis and inside of it, and 

 there is no pivot movement within the pelvis, nor restitution nor 

 rotation outside of it; or, on the other hand, the hips and shoulders, 

 which were engaged transversely at the upper strait, place them- 

 selves in an antero-posterior direction to pass through the vulva — in 

 which case the head is the only part that does not turn on its axis. 



2. Calcaneo-Posterior Position. 

 4th position of Baudelocque, MM. Gardien, Desormeaux, &c.; 10 in 538, Ma- 

 dame Lachapelle; 6 in 234, Madame Boivin. 



783. Under the title of fourth position, Baudelocque comprised 

 all the cases where the dorsal surface of the foetus looks towards 

 any point of the posterior half of the superior strait, and not merely 

 those in which it is turned directly backwards, as we might be 

 tempted to believe from reading a great number of modern works. 

 In this respect he has only imitated Mauriceau, Dionis, De La 

 Motte, Portal, Smellie, Asdrubali, &c. 



In the usual folded state of the foetus, the soles of the feet, the 

 fore parts of the legs, and the forehead and abdominal surface of 

 the child are directed forwards. The lower limbs being more or 

 less rapidly extended and elongated by the uterine contractions, 

 they pass through the vagina, and reach the vulva; the hips soon 

 follow, and sometimes pass the superior strait in the direction of the 

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