323 UNNATURAL EUTOCIA. 



waters run off, and sometimes even much later than that. If the 

 amnios does not give way until after the orifice is properly dilated, 

 the legs and thighs follow the feet immediately, and the hips, which 

 traverse the superior strait in a diagonal position, soon reach the 

 vulva. Ill the contrary case, all these parts descend slowly, and by 

 degrees, with each returning pain. The frelal pelvis, before it en- 

 gages into the inferior strait, generally performs a rotation upon the 

 right anterior and left posterior inclined planes of the excavation; 

 the left hip occupies the arch of the pubis, Avhile the right hip goes 

 to fill up the hollow of the sacrum. The whole child bends upon its 

 anterior or left side; the belly next passes through the os uteri; the 

 elbows, pressed against the ribs, or somewhat in front upon the 

 breast, yield to the contractions of the womb, and descend along 

 with the thorax into the excavation. The shoulders follow the 

 chest through the abdominal opening of the pelvis, where they re- 

 main in the same direction they affected at the commencement of 

 the labor, that is to say, diagonally, the right before the lefi sacro- 

 iliac symphysis, and the left behind the right acetabulum. When 

 below the strait, they are subjected to the same pivot motion as the 

 hips, and like them, are soon placed in the antero-posierior direc- 

 tion. The head, strongly flexed, follows the upper part of the breast; 

 the ovoid which it represents engages with its apex foremost; its 

 occipito-mental diameter is parallel with the axis of the strait, the 

 plane of which soon becomes parallel to the occipito-bregmatic cir- 

 cumference; the bi-parietal and occipito-bregmatic diameters mea- 

 sure the oblique diameters; in fine, the relations of the head to the 

 upper pelvic circle are absolutely the same as in the first position of 

 the vertex; there is only this difference, that the small, instead of 

 the large extremity of the cone represented by the head, videl. the 

 chin, the face and base of the skull — instead of the superior oval and 

 occiput — advance foremost. 



779. The root of the umbilical cord, the abdomen, and the lower 

 part of the thorax are now emerged; the left elbow appears at the 

 top of the pubic arch; the right elbow, arm and shoulder slide gra- 

 dually along the sacrum and perineum, and successively appear in 

 front of the posterior commissure of the vulva, which strongly raises 

 the trunk of the foetus up towards the mons veneris; so that the 

 shovdder that is in front does not commonly disengage itself until 

 after the other, although the corresponding elbow had appeared at 

 the vulva first. Immediately after this, if not supported, the child 

 falls backwards again by its own weight, and rests on the anterior 

 edge of the perineum; a kind of movement of restitution which 

 again carries the left shoulder to the right, and the right one to the 



