78 



OBSTETRICS. 



Fig. 22. 



pubis, and the forehead on the right posterior, into the hollow of the 

 sacrum, and the head is born in such a manner, that whilst the 

 occiput rests against the os pubis, the point of the chin, followed by 

 the rest of the face, sweeps over the perineum, as the head turns on 

 its lateral axis from below upwards (Fig. 23). 



Fig. 23. 



" There is no essential difference in the mechanism of the labour, 

 when the sacrum is at the right acetabulum, except that the rotation 

 is reversed ; the right hip and shoulder rotate on the left anterior in- 



