DYSTOKIA FROM TRANSVERSE PRESENTATIONS. 489 



movements of the mother ; deviation of some part of the foetus — especially 

 of the head; hydrocephalus, monosomianism, etc., have all been noted 

 at times as a cause of transverse presentations. Deformed head may 

 also lead to this presentation, especially if it is distorted as in Fig. 84. 



These presentations are essentially dystokial ; as it is evident that the 

 foetus, if of normal size, cannot pass cross ways or sideways through the 

 pelvic canal, which- barely affords space for its passage longitudinally. 

 Birth, therefore, cannot take place without assistance ; version must be 

 practised in order to change the presentation, and one or other of the 

 extremities of the oval mass which the body of the foetus represents 

 must be brought towards the inlet. The malpresentation, through hin- 

 dering birth greatly, endangers the life of the young creature, and espe- 

 cially if it be a foal. 



As mentioned at page 230, the transverse presentations of the body 

 may be limited to two kinds : the dorso-lumbar, in which some part of the 

 back presents at the inlet ; and the sterno-abdomitial, in which the lower 

 part of the body (belly) offers. In the latter presentation, the limbs first 

 enter the os and genital canal, and they may be two (a hind and fore), 

 though more frequently three or all of them may be engaged j the head 

 may or may not have passed into the inlet. 



N 



Dystokia from the Dorso-lumbar Presentation. 



To diagnose this cause of dystokia — or back presentation — is not 

 always easy. Labor has being going on for some time, the " waters " 

 have escaped, and though the straining may be very energetic — even 

 violent — yet nothiiig is seen of the foetus. When the hand is introduced 

 into the genital canal, in order to discover the situation of the foetus and 

 the nature of the obstacle which hinders birth, it encounters at first a 

 more or less rounded surface, which does not offer any special character 

 by which it might be recognized. The hand is then passed deeper 

 into the uterine cavity, and turned in every direction over the body of the 

 foetus (for such it is), so as to find some parts which may be distinguished, 

 and by which the position of the young creature in the uterus may be 

 learned. 



By this methodical exploration, the obstetrist recognizes that the body 

 of the foetus is more or less curved in the back, one of the regions of 

 which presents at the inlet ; while the head and limbs, more or less en- 

 tangled with each other, and more or less accessible to the hand, are 

 directed towards the fundus of the uterus. It now remains to discover 

 the region which first met the hand, and the following memoranda will 

 assist in achieving this point. The withers are" recognized by the prom- 

 inences which the spinous processes form at this part ; the thin wedge- 

 shaped outline of the part ; and the hair of the mane which, in the foal, 

 ends here. The lumbar region may be distinguished by the large and 

 almost level surface it offers ; the projecting external and internal angles 

 of the coxae in its vicinity ; the hollow of the flank leading to the thigh and 

 stifle. The dorsal region, or back, is discovered by the arches of the ribs 

 springing from each side, with the intercostal spaces. 



Having diagnosed the presentation, the positioti must now be determined, 

 and this is done by ascertaining the direction in which the head lies. 

 With regard to this, we pointed out at page 231 that there were three 

 positions of the foetus : i. The cephalo-ilial positions^ two in number, in 



