DYSTOKIA DUE TO THE FoUELIMm^. 



441 



shoulder presentations. With the smaller Ruminants, owing to the 

 formation of the pelvis, birth is not often impeded. With the Sow 

 and Garni vora — multiparous animals — this might almost be designated 

 a normal presentation. 



It will readily be perceived how one or both of the anterior members 

 bent back under the body will prove an obstacle to the passage of the 

 foetus, after what has been said with regard to the relative dimensions 

 of the young creature and the pelvis of the mother. The shoulder or 

 shoulders, and the muscles in this region, are the cause of dystokia — 

 more especially the flexor brachii, which constitutes a thick and some- 

 what tendinous elastic mass between the scapula and upper end of the 

 fore-arm. This muscular mass forms a very prominent obstacle on 



Fig. 131. 



A.STBBIOB PRtSKSTATION, D0R80-SaCR.\L PoSITIO.V : BoTH FoEK-LlMUa OOMPLKTKLY 



RETAINED. 



the side of the chest when the limb is thrown back. There is also the 

 large levator humeri muscle adding to the increased volume of the 

 thoracic region, as well as the elbow and fore-arm. 



On exploration in this complication, the head is found to be in a 

 good direction, the hand encountering it either in the pelvis or towards 

 the inlet, or it may even protrude into the vulva, according to circum- 

 stances. The fcetus, if a Calf, may be yet alive ; if a Foal, it is nearly 

 always dead. If only one limb is completely retained, the other will 

 be in a normal position — alongside or under the head (Fig. 130). If 

 both limbs are retained, though the head may appear in the genital 

 canal or at the vulva, yet nothing can be discovered of them in the 

 pelvis, they being entirely lodged in the uterus. At each pain the 



