386 FCETAL DY ST OKI A. 



large, the cranium may offer an invincible obstacle to spontaneous 

 delivery, notwithstanding the most powerful labour pains. 



And, iDesides, the mechanism of parturition in such cases varies with 

 the presentation — anterior or posterior. The head of the hydrocephalic 

 foetus being more or less spherical — instead of conical, as in the normal 

 condition — it results that this part, when the young creature is pressed 

 upon by the uterus, no longer acts as a wedge to gradually dilate the 

 OS uteri. The head certainly commences the work of dilatation, but in 

 a very incomplete manner, and when the jaws — particularly the upper 

 one — have cleared the os, further progress is checked by the voluminous 

 forehead. If the hand is introduced into the vagina, the cervix uteri is 

 found to be contracted on the nose or jaws of the foetus ; and the delay 

 in further expulsion depends upon the size of the cranium, the pro- 

 trusion of the uterus into the pelvic cavity, and the exhaustion of the 

 organ by futile contractions. 



In the posterior presentation, birth takes place in the manner already 

 described ; the hinder extremities advance through the os, then the 

 body and neck, and birth is apparently taking place satisfactorily until 

 the head reaches this aperture, when further advancement is stopped — 

 the resistance to expulsion being in proportion to the volume of the head. 



Not infrequently, with such a condition of the foetus we have also a 

 malposition to complicate matters. 



Diagnosis. 



In the anterior position, there is not much difficulty in diagnosing the 

 presence of hydrocephalus ; as the hand can feel the voluminous spherical 

 cranium beyond the muzzle and eyes, with the ears on each side, and 

 its unequally resisting surface — hard in some parts, soft or fluctuating 

 in others. When, however, there is a malposition of the foetus, then it 

 is sometimes more difficult to discover the hydrocephalus ; and often 

 this cannot be done until the position is remedied. The head should 

 be sought for in every case, and it will be recognised by the mouth, eyes, 

 and ears ; after which the size, consistence, and form of the cranium 

 can be estimated by passing the hand over it. 



In the posterior presentation, hydrocephalus has been recognised 

 while the foetus was still in the uterus. The greatly enlarged head 

 may be felt per rectum, or even through the abdominal walls. But, as 

 a rule, it is only at an advanced period of labour, and when the body of 

 the young creature is already beyond the os, and perhaps without the 

 vulva, that a difficulty is discovered and the cause sought for. 



In such a case manual exploration is necessary, and this should be 

 effected, if possible, by passing the hand between the foetus and the 

 wall of the vagina. This is difficult if the body is still in the passage, 

 and it may be requisite to have recourse to traction to withdraw it 

 therefrom. If, however, it is beyond the vulva, then the hand can be 

 easily passed along the neck as far as the head, when the real state of 

 affairs can be discovered. 



Indications. 



The indications for treatment in cases of dystokia from hydrocephalus 

 alone, without reference to such a complication as malposition of the 

 foetus, are few and simple. 



"When the hydrocephalus is not considerable, judicious traction will 

 often accomplish delivery ; and several cases are on record in which 



