490 LOCKED-HEAD. 



pubis and sacrum, without being able to advance or recede, and so 

 that it is almost impossible to apply the instrument to it. Accord- 

 ing to De la Motte, the head, when locked, is griped by the bones 

 of the pelvis, like the key stone in an arch. Roederer presents 

 another view of it: he thinks that in order to constitute locked 

 head, the head must be so embraced in the strait, or in the excava- 

 tion, by every point of its circumference, that a lamina of metal or 

 the smallest probe cannot be passed between it and the organs of 

 the woman. Baudelocque says that the head is locked, whenever 

 it is fixed at the superior strait by the two extremities of one of its 

 diameters, so that it can neither advance under the influence of the 

 natural powers, nor be forced back by the hand of the accoucheur. 

 Baudelocque's definition, which has been adopted by all modern ac- 

 coucheurs, and slightly modified by M. Desormeaux, is without con- 

 tradiction the most correct, and may be construed as follows: the 

 head is locked in the pelvis whenever two diametrically opposite 

 points of its superficies are so compressed that it cannot possibly 

 descend under the influence of the expulsive power alone, and when 

 it cannot be pushed up without the very greatest difiiculty. The 

 locked-head, according to the view of it presented by Roederer, or 

 paragromphosis, cannot possibly occur. Madame Lachapelle will 

 not even admit the existence of any species of it, and thinks that all 

 that has been written under that title ought to be referred to vicious 

 conformations of the pelvis, to bad positions of the head, or, lastly, 

 to powerful and permanent contractions of the uterus. 



1098. However this may be, locked-head has become very rare 

 at the present day, and De Bruyn, who pretends to have met with 

 eight hundred cases of it in the course of forty years, Berkman and 

 Titsing, who cite two hundred and sixty-two cases in nineteen 

 years of practice, must have had a different idea of it from ours. 

 It is to me evident, from the accounts given by Camper on this sub- 

 ject that the Dutch accoucheurs gave the denomination of locked- 

 head to all cases in which the head, from being arrested in any way 

 in the pelvis, makes the employment of Roonhuysen's lever necessary; 

 so that what they have said concerning locked-head has almost no 

 connection with what has since been written by Baudelocque under 

 that title. Dr. Dewees, who treats of locked-head upon the princi- 

 ples of Baudelocque, is astonished that he scarcely ever meets with 

 it, and thinks that the circumstance depends upon the American wo- 

 men having better formed pelves than the European women; but he 

 would probably hold a different language if he knew that Madame 

 Lachapelle never met with it at all, and that but a few instances of 

 the kind are met with in the course of a year. 



