246 



NORMAL PARTURITION. 



SO that the foetus experiences much difficulty in moving along. The 

 relations are still more reversed between the transverse diameters of 

 the foetus and those of the pelvis when the first correspond to the 

 inferior bis-iliac diameter of the mother. 



Positions in the Posterior Presentation. — In this the croup or 

 breech first presents at the pelvic inlet. The lumbar region of the 

 foetus, which is the determinate point, may be directed towards the 

 sacrum, the pubis, or the right or left branch of the ilium of the 



Fig. 76. 

 Right Cephalo-ilial Position in the Dorso-lumbar Presentation. 



female towards the oblique diameters of the pelvic cavity. Hence we 

 have eight positions, as in the preceding presentation. These are : 



1. Lumbosacral Position. — The foetus is in what some authorities 

 have called a " natural " position (Fig. 75), but which is asserted by 

 others to be unnatural. The loins are towards the sacrum of the 

 mother, the right coxo-femoral articulation towards the right ilium, 

 and the left articulation towards the left ilium. This is sometimes 

 named the first j^osterior position. 



2. Luviho-jxuhic Position. — Some practitioners designate this the 

 posterior reversed position. The foetus is lying on its back, its croup 

 and loins corresponding to the pubis of the mother, while the limbs 



