POSITIONS OF THE FOiTUS. 



243 



Tlie position has accordingly been defined to be the relation of a 

 determinate point on the surface of the foetus, to an equally determinate 

 point of the pelvic circumference. The poiuts, so far as tlie mother is 

 concerned, may be determined once for all, and they will always remain 

 the same for every presentation ; they may be, for instance, the sacral 

 region above, the pubic below, and tlie two ascending branches of the 

 ilium at the sides. If with the fcctus we select any region — say the 

 withers — and put this part in relation with any of these four points of 

 the pelvic circumference, we shall have four successive and easily 

 recognised positions. If, therefore, we first give the name of the region 

 in the ftctus, and next that of the pelvic circumference with which it is 

 in relation, we have a ready means of designating the positions — de- 



Fig. 73. 



Normal Position ok the Futis i.v thk Mark (Thiri) Sta(;k.). Dobso- 

 SACKAL Position. 



scribing the fcetus to be in a vertebrosacral position, for instance, when 

 its vertebral region is in relation with the micrum of the mother. The. 

 fixed points may be invariable in the latter ; but they cannot be so with 

 the fcctus, as they will vary with each presentation. 



With regard to the anterior and posterior presentations, Rainard has 

 selected the fixed points as follows in tlie loiujitudiual presentations : 

 for the first, he has taken the spinous processes of the dorsal vertebra; 

 in th(! region of the withers ; for the second, the lumbar vertebra\ 

 For the positions in the other two presentations, he has not been so 

 fortunate in a designation, in the opinion of Saint-Cyr, who has very 

 judiciously proposed others which are more explicit and comprehen- 

 sible. The latter gives the various positions which should be recognised 

 in each presentation, as follows : — 



, A. Anterior Position. — The chest of the fatus is at the pelvic 

 inlet, and it is desired to make known what relation this part has to 



