EMBRYOTOMY. 541 



Puncture of the Cranium. 



In order to allow the escape of fluid from tlie cranium — as in hydro- 

 cephalus — and thus permit the birth of the foetus, a simple puncture is 

 often all that is necessary. The lluid having escaped, the thin fra<,Mle 

 bones of the cranium readily collapse from the pressure they undergo in 

 the pelvic cavity ; so that the head and body can be removed by 

 traction. 



Supposing the presentation to be anterior, it is first necessary to 

 fix the head, unless it is firmly wedged in the passage ; this fixation 

 may be etYected by using a head-stall, Schaack's head-stall forceps, or 

 even a cord on the lower jaw : exercising suflicient traction on the cord 

 to prevent the head from slipping from under the hand of the obstetrist 

 during the operation. 



The head may be punctured by a scalpel, straight bistoury, finger- 

 knife, or even the finger in certain cases. If a long-bladed instrument 

 is used, there is sometimes a good deal of risk, so far as the maternal 

 organs are concerned ; ic is advisable to wrap twine, tow, or tape, 

 around a good portion of the blade towards the handle. 



The best instrument, if it is at hand, is a long, medium-sized trocar 

 and cannula, the end of the latter fitting closely on the stalk of the 

 trocar, which should be very shax'p. It is introduced safely into the 

 genital canal by drawing the point sulViciently far back into the cannula 

 to be entirely concealed. This end is then seized between the lingers 

 and thumb in such a way that the index-finger extends a little beyond 

 the extremity of the cannula ; the other three fingers holding it in the 

 palm of the hand, while the right hand sustains and guides the instru- 

 ment. Should the trocar not fit the cannula tightly, the play between 

 the two renders their introduction somewhat dilVicult, and the point 

 may glide through and wound the operator. The trocar may, in such 

 a case, be pushed quite through the cannula, and the point fixed in a 

 cork, which can readily be knocked ofi" by one of the fingers when the 

 instrument has reached the head of the foetus. Having an-ived at this 

 part, the proper spot for puncture is selected, and then the instrument 

 is applied to it — perpendicular to its surface if possible, to prevent 

 slipping. The trocar is made to penetrate slowly by a slight rotatory 

 motion from side to side, and when all resistance ceases the cranium is 

 perforated. This perforation should not be made at the sutures, if they 

 can be avoided, as they overlap and close the opening. The cannula is 

 now held firmly in its place by the left hand, the trocar is withdrawn ))y 

 the right, and the fluid escapes. The instrument should be sutViciently 

 long for the end to be near, or even outside the vulva, when the point 

 is on the cranium of the foetus. 



There is no difficulty in performing this operation when the head 

 presents first, even though it should not have entered the inlet, so long 

 as it is easily accessible to the hand. With the posterior presentation, 

 however, the operation is troublesome ; as owing to the body of the 

 fcctus occupying the passage, it is extremely difficult to pass the hand 

 armed with the trocar so far as the head. Nevertheless, it may bo accom- 

 plished in many cases by patience and tact. There is no reason why the 

 trocar and cannula should not be passed through the mouth of the fcrtus 

 in some cases, and made to penetrate the cranium at the base of the 

 skull, when the frontal region cannot be attained. If the head cannot 

 be reached in this presentation, then the body of the young creature 

 must be divided, and the parts removed until the head can be manipulated. 



