TOO SMALL A PELVIS. 495 



1106. To attain this object, the accoucheur ought to know the 

 exact dimensions of the head and pelvis, in those diameters which 

 correspond to the diameters that correspond to each other in the 

 different stages of labor; also, to know how far the head is capable 

 of being reduced, and what amount of courage and energy are likely 

 to be exhibited by the woman; but these notions can only be ac- 

 quired approximatively. Notwithstanding the numerous cephalo- 

 meters proposed by various authors, and in spite of the means re- 

 cently indicated by M. Fouilhous, we must still depend upon the 

 finger for the most certain result under such circumstances: and, 

 with the exception of M. Flamant, what practitioner is so bold as 

 to dare to pronounce that the dimensions of a head he has just 

 examined are, within from two to three lines, of precisely such or 

 such an amount? The degree of solidity of the pelvis, the form of 

 the contracted strait, and the direction of its axes, also deserve the 

 most serious attentions: for example, the symphysis may be soften- 

 ed to such a degree as to admit of the bones sliding one over the 

 other, so that one os pubis may extend in front, while the opposite 

 coxal bone falls backwards, which would render the corresponding 

 oblique diameter so much longer. According to Deventer and Ma- 

 dame Lachapelle, the two hip bones may also be both carried for- 

 wards by the forcing of the sacrum into the space between them, 

 and thus give rise to an unexpected augmentation of the sacro-pubic 

 diameter. If the superior strait is of the shape of a figure 8, or if 

 the contraction occupies only one side, the head being situated trans- 

 versely, with the occiput towards the widest part of the pelvis, may 

 sometimes traverse the canal notwithstanding a considerable degree 

 of contraction. 



Where the axis of the strait approaches that of the spine, the two 

 extremities of the bi-parietal, or the occipito-bregmatic diameter will 

 be compelled to engage at the same time, and will require a space of 

 about three inches. Should it, on the contrary, be very much in- 

 clined to the front, one of the parietal protuberances might engage 

 before the other, so as to give a gain of three or four lines in the act 

 of passing through the pelvic circle. 



On the other hand, a head that is very flexible, and energetically 

 urged onwards by the uterine and muscular contractions of a vigo- 

 rous woman, may be elongated and moulded in the passages, be con- 

 siderably reduced (Denman says, to one-third of its original vo- 

 lume), and, according to Baudelocque, attain to the length of eight 

 inches, while its thickness is proportionably diminished; it may be- 

 come so much flattened as to pass through a strait of two inches 

 and a half, and recover its ordinary volume within the excavation, 



