Interlocking of the Fetal and Maternal Pelves 775 



the perpendicular to the fetal spine. The error in the direction 

 of traction causes the fetal ilia to become firmly lodged against 

 the anterior border of the maternal ilia, and the more violent the 

 traction, the firmer the interlocking. 



When the fetal pelvis is large and the external ilial tuberosi- 

 ties prominent, the hips may offer serious resistance in passing 

 the pelvic inlet, even without the complication of misdirected 

 traction. 



With misdirected traction we have twice seen cows tied firmly 

 by the head to a post, with one or two horses hitched to the 

 fetus and pulling their utmost in an attempt to bring away the 

 calf, but without avail. 



The symptoms and diagnosis of this form of dystokia require 

 but little consideration. The fetus, possibly rather large, gen- 

 erally offers in the normal anterior presentation, and advances 

 somewhat slowly until the hips have reached the pelvic inlet, 

 when the progress is stopped and the fetus cannot be advanced 

 by traction so long as it is applied in a direct line, parallel to the 

 long axis of the body of the mother or .somewhat upwards. If 

 the operator can succeed in inserting his hand along the fetus 

 into the uterus, he will find that everything is apparently normal, 

 except that the pelvis of the fetus is firmly wedged against that 

 of the mother and seems immovable. We know of but one con- 

 dition from which we need to differentiate it, and that is the 

 double monstrosity known as pigodidymus aversus. Fig. 129. 



The indications in this form of dystokia are : 



1. The Application of Traction in the Proper Direction. 

 When a fetus is advanced without serious difficulty until it has 

 reached the hips, and is in every way normal, there is no good 

 rea.son why its extraction should not be readily completed, if care 

 is taken to apply the traction directly downward toward the feet 

 of the mother, according to the technic given on pages 586 and 

 640. Some suggest release by partial rotation. 



2. Embryotomy. Failing to bring about extraction under 

 moderate force, the obstetrist should at once resort to embryot- 

 omy, consisting of the destruction of the pelvic girdle, as already 

 described on page 649. 



