432 DYSTOCIA. 



and on the other the scapulae and back part of the neck, might 

 serve to show which way the head is directed. 



The sternum, the ribs and clavicles, above which we can also 

 sometimes feel the front of the neck, indicate presentations of the 

 anterior face of the thorax. 



Where the os uteri is largely dilated and the membranes ruptured, 

 and the presenting part is not too high up in the pelvis, and has not 

 had time to swell and alter its shape under the influence of the ute- 

 rine contractions, it is in general prettj' easy to distinguish the differ- 

 ent positions of the trunk from each other; it is at least always pos- 

 sible to avoid confounding them with those of the head or pelvis; 

 but in the contrary circumstances the most consummate experience 

 is sometimes deceived, and it is often impossible to establish a cer- 

 tain diagnosis until after having carried the hand into the womb. 



975. Choice of the hand. Where the bag of waters is still un- 

 broken, or the foetus retains a considerable degree of mobility, it is 

 useless to delay about the choich of a hand to operate with: the one 

 that is most easily used is to be introduced, or the one which habi- 

 tually brings down the child in the least unfavorable position; 

 where the position has not been ascertained, or is merely a matter 

 of doubt, the practitioner ought to act in the same manner, or may 

 make use of the hand commonly employed in operating for those 

 positions most frequently met with; if, however, there should occur 

 any difficulty after reaching the womb; it is best to withdraw it and 

 introduce the other hand. 



In cases where the presentation is well determined, we may 

 know at once which hand is most favorable to the success of the 

 operation; this is moreover liable to vary according to the kind of 

 manosuvre about to be executed, or which it is indispensably neces- 

 sary to attempt, 



976. For those inclined positions of the head and breech which 

 do not require immediate version by the feet, the left hand ought to 

 be preferred. Whenever the deviated parts correspond to some 

 portion of the right half of the pelvis; the right hand, on the con- 

 trary, in the opposite deviations, and either of them, indifferently, if 

 the deviation takes place directly front or back. The cephalic ver- 

 sion ought to be subjected to the same rule of practice. 



977. For the feet, knees, or breech, those positions in which the 

 posterior surface of the foetus looks towards the left side of the pel- 

 vis, are best operated on with the left hand, and the inverse posi- 

 tions with the right hand, although it may be most frequently in our 

 power to do just the contrary if we please. 



978. When the vertex presents first and we have to bring down the 



