84 OBSTETRICS 



Mechanism. — The feet meeting with no resistance to fix them, are 

 liable to change their position during their descent until the hips 

 enter the brim, which they do precisely as in breech cases ; the me- 

 chanism, therefore, is the same, and does not require a further de- 

 scription. 



Treatment. — The same rules "apply to the treatment of presenta- 

 tions of the inferior extremities that were laid down in breech cases, 

 with the additional caution, not to yield to the temptation to pull 

 down the feet ; the dilating part is already too small for safety, and 

 if it be diminished by this procedure, the child will almost certainly 

 be lost by pressure upon the cord during the descent of the head. 



PRETERNATURAL LABOUR. 



Preternatural labour, or dystocia, signifies a faulty, or irregular 

 labour, the course of which is unfavourable, and in which the assis- 

 tance of the obstetrician becomes necessary. It will be remembered 

 that this definition applies to all cases of labour, without reference 

 either to presentation or position, in which manual assistance becomes 

 necessary. 



According to Velpeau, the causes that render labour difficult, 

 depend either upon the mother or the child. Some of them are 

 unforeseen, or do not occur till the moment of parturition ; the title 

 of accidental may be appropriated to them. Others exist before- 

 hand, and render the labour necessarily difficult ; they merit the 

 denomination of pre-existing causes. 



The accidental causes are : any serious disease, such as inflamma- 

 tion of the brain or its coverings, the lungs, pleura, peritoneum, 

 or uterus, &c., which takes place during labour ; any hemorrhage 

 sufficiently abundant to endanger the life of the mother or her 

 offspring ; convulsions, syncope, laceration of the womb, the prema- 

 ture escape of the cord, hernia, aneurism, asthma, great debility, 

 &c., and some positions which do not become bad until after the first 

 pains. 



The pre-existing causes arc : deformities of the pelvis, malforma- 

 tion or disease of the organs of generation, calculus in the bladder, 

 fibrous or other tumours in the excavation, deformities in respect to 

 height, transverse positions, monstrous conformation and diseases of 

 the foetus. 



As these different causes are in reality only complications of labour, 

 it follows that dystocia comprises all cases of complicated labour, as 

 eutocia comprehends all simple labours. 



From the occurrence of any of the above-mentioned causes, one 

 of the following operations may become necessary, to wit : turning, 

 the application of the forceps, or craniotomy. The first of these 

 most frequently becomes necessary in cases of transverse positions 



