38 OF THE PELVIS. 



malacia, there remained a space of about three lines only in the an- 

 tero-posterior diameter, and only about half an inch betwixt the iliac 

 fossae.* Baudelocque cites a case in which there were only nine 

 lines from the sacrum to the pubis. A contraction almost as great 

 as the one just mentioned, is observable in a specimen that I saw 

 in the Museum de I'Ecole de Medecine; however, any body can 

 understand how many shades there may be between these extreme 

 contractions and the normal dimensions of the pelvis. 



92. The inferior strait is perhaps more frequently enlarged than 

 contracted; when the base of the sacrum is depressed towards the 

 pubis, or the pubis driven backwards towards the sacrum, it almost 

 always is in the direction of a see-saw movement, which separates 

 the coccyx more or less from the top of the pubic arch. Although 

 it may be laid down as a general rule that the inferior strait enlarges 

 while the superior strait contracts, it is, nevertheless, possible that 

 they may both be narrowed at the same time, and that too in their 

 corresponding diameters. 



93. The approximation of the tuberosities of the ischia towards 

 each other, too great a straightness, or a triangular form of the pubic 

 arch, coinciding almost always with a long symphysis pubis, give 

 birth to what is called barrure, the most coiiiiiion and dangerous of all 

 the deformities of the perineal strait; for as the foetal head must pass 

 through the pubic arch, rather than behind the ischia where the soft 

 parts arrest it, the barrure renders the delivery extremely difficult; 

 the retroversion of the coccyx does no good in this case, and if the 

 child is born at last, it is at the expense of an extensive laceration 

 of the perineum. 



94. The coccyx, also, very often becomes almost horizontal, and 

 may, by rising upwards, more or less affect the coccy-pubal diame- 

 ter, especially where the base of the sacrum is thrown back. It 

 also pretty frequently happens that one of the ischia with its ramus 

 inclines towards the centre of the strait, while the opposite ischium 

 and the coccyx do not alter their position. In fine, the varieties of 

 form are here less numerous than in the superior strait; but the de- 

 grees of contraction should be understood in the same manner. 



95. Faults of the excavation coincide almost always with the con- 

 tractions of one or the other strait, and sometimes with both of them 

 simultaneously. They depend either on too great, or on an insuffi- 

 cient curvature of the sacrum. 



96. In the former case the bone is bent, as it were, upon its an- 



* In a woman who had already had six children, M. Nsegele saw such a de- 

 formity of the pelvis as to leave only two lines on the left, and six lines on the 

 right between the fourth lumbar vertebra and the superior brim of the symphysis 

 pubis. 



