PELVIC PRESENTATIONS. 79 



clined plane, and the left hip and shoulder on the right posterior 

 inclined plane ; the occiput on the right anterior, and the forehead 

 on the left posterior inclined plane. As before mentioned, when the 

 sacrum is to the pubes, as it descends it becomes oblique, and then 

 the mechanism is precisely the same as above described. (Figs. 22, 

 23 describe these.) 



" As in positions of the cranium, the swelling of the integuments 

 is chiefly met with on that parietal bone which, during the passage 

 of the head, is situated lowest, and on that spot with which it enters 

 the external passage, so in this case, the livid-coloured swelling 

 appears on that part which, directed forwards, was situated lowest 

 during the passage of the nates, and with which the nates were 

 born." 



In the second chief position, viz. : with the anterior surface of the 

 child corresponding to the anterior abdominal parietes of the mother, 

 or in other words, with the sacrum of the child to the sacrum of the 

 mother, the same efl^ect is produced by the expulsive action as be- 

 fore. The breech descends to the outlet of the pelvis ; a slight turn 

 is effected; one of the ilia (and it is generally the left) appears un- 

 der the arch of the pelvis, the other traverses the perineum ; the 

 breech and legs escape, the shoulders pass the brim, and descend 

 until they press upon the structures at the outlet ; one escapes under 

 the arch of the pubes, the other follows the curve of the sacrum, 

 and the head is propelled into the cavity of the pelvis, with the face 

 looking to one side, and the occiput to the other. 



It might be supposed, from the position of the head at the com- 

 mencement of labour, with the face looking forwards, that the occiput 

 would fall into the hollow of the sacrum, and the^ace emerge under 

 the pubes ; but this is not the case ; for when the shoulders are born, 

 and the head is in the pelvis, the face is directed to one side or the 

 other, exactly as in the sacro-anterior position ; and a precisely 

 similar turn is effected, the face falling into the hollow of the 

 sacrum ; so that the foetus in its exit makes a semicircular rotation, 

 the face being placed forwards at the commencement of labour, and 

 being expelled through the outlet over the sacrum and perineum. 

 Dr. Ramsbotham, from whom the above description is taken, says 

 farther, " I believe that in no instance, if the case were left entirely 

 to nature — provided the child and pelvis were of the common size 

 and form — would the face be expelled under the arch of the pubis." 

 Dr. Collins also confirms it. Dr. Naegele mentions this last as a 

 deviation from the ordinary mechanism of breech cases. He also 

 describes another deviation, in which the chin departs from the 

 breast, and the head enters the pelvis, after the birth of the body, 

 with the occiput pressed against the nape of the neck, and the vertex 

 corresponding to one or other ilium of the mother. As the head 

 presses lower into the cavity, the vertex turns gradually more and 



