Presentations of the Fetus 



531 



mother, but even the transverse axis of the fetal chest must ba 

 decreased. We ma}', therefore, recognize two normal attitudes 

 of the fetus in relation to its long axis — the anterior and pos- 

 terior presentations, in which the anterior or posterior end of the 

 fetus respectively presents at the pelvic inlet. 



The mere fact that the spinal axes of the mother and fetus are 

 parallel does not insure that the attitude of the fetus is normal 

 or that parturition can take place without aid, but merely that, 

 upon examination, some portion of the anterior or posterior part 

 of the body is met. 



Fig. 88. Posterior Presentation. 

 Dorso-sacral position. (St. Cyr. ) 



Not every fetus, however, is presented in such a way that its 

 long axis corresponds to that of the mother. Instead, it may be 

 perpendicular to it, so that the fetus presents transversely, in 

 which instance it cannot be born without a correction of its pre- 

 sentation, and therefore becomes abnormal. 



The fetus may present transversely at the pelvic inlet, either by 

 its dorsal or ventral surface, and consequently there may occur a 

 dorsal or ventral presentation. 



