PRESENTATION OF THE VERTEX. 309 



those, the study of which is really important. We are not, how- 

 ever, on this account to deny the existence of the directly anterior 

 and transverse positions established by Baudelocque, M. Flamant, 

 and Madame Lachapelle. 



754. I have treated in greater detail of the occipito-pubic and 

 sacral positions than of the occipito-iliac positions, because their 

 mechanism presents some peculiarities which it is well not to be 

 ignorant of, for the doctrine of Baudelocque being extensively 

 known, it might be attended with some inconvenience, were I to over- 

 look positions admitted by that author to exist, which, though they 

 are of rare occurrence, yet really do occur, and substitute for thera 

 others equally rare, and which, moreover, soon become confounded 

 with the oblique ones. 



755. When Madame Lachapelle says that the occipito-iliac are 

 more frequently to be met with than the fronto-acetabular positions, 

 she must surely be misled by some preconceived idea. Previously 

 to the descent of the head into the excavation, it is often difficult 

 to say whether the occiput looks exactly towards one of the ex- 

 tremities of the transverse diameter, rather than a few lines for- 

 wards or backwards of it, or to know whether it constitutes a trans- 

 versal position, rather than an oblique one very much inclined: 

 further, as the author herself admits that the head remains but a 

 short time thus directed towards the iliac fossae, either the occiput 

 or forehead soon deviating in front to gain the pubic arch, and the 

 left occipito-iliac position being the most common of the two it is 

 manifest that the transverse positions are completely converted into 

 the corresponding oblique ones, and that they do not deserve a par- 

 ticular description. 



756. Anomalies. In some positions of the vertex the movements 

 of the head seem to deviate wholly from the ordinary march of a 

 labor; for example, it may happen, and indeed it does happen 

 pretty often, that after having passed obliquely through the superior 

 strait, it places itself transversely in the excavation, where it re- 

 mains for a longer or shorter time previously to performing its pivot 

 motion; in other cases this motion is not performed at all, or but 

 imperfectly; the head, therefore, passes the inferior as it did the 

 superior strait diagonally, or even emerges from it in a transverse 

 position, so as to bring the occipito-bregmatic, into parallelism with 

 the bi-sciatic diameter. In some other instances, the occiput upon 

 escaping from the vulva turns in a direction directly contrary to that 

 it ought to pursue, provided the restitution were regular; it was in 

 this way that Solayres and Baudelocque saw, and that I myself have 

 seen, the face, in a left occipito-acetabular position, turn towards the 



