134 OBSTETRICAL PHYSIOLOGY. 



Situation. 



The uterus cannot change its form and volume without its situation 

 becoming altered. Before, and until a certain time after conception, 

 the body of the uterus is contained in the pelvis, but as it and the foetus 

 increase the position changes, and this also causes an alteration in the 

 situation of other organs. In the Mare the uterus gradually displaces 

 the pelvic flexure of the colon lodged in that cavity, and passes forward 

 below that viscus, towards and beyond the umbilicus, to rest on the 

 floor of the abdomen, in proximity to the diaphragm, stomach, and liver, 

 near the termination of pregnancy. In its development it is situated 

 chiefly in the middle line of the body, slightly inclining to the left, 

 because of the large mass of the colon occupying the right flank. 



In Euminants, the uterus pushes the rumen and caecum out of the 

 pelvis, presses the mass of intestines to one side, and extends between 

 the right sac of the rumen and the abdominal walls. The presence of 

 the rumen in the left flank causes it to deviate somewhat to the right. 



In mitltijjarous animals, in which the young are placed end to end in 

 the cornua, the latter rest on each side of the floor of the abdomen and 

 curve upwards ; in the Pig they incline somewhat to the right side, though 

 in all animals each cornu lies above its corresponding mammary line. 



While these changes are taking place, the broad or lateral ligaments 

 are facilitating them by becoming unfolded and lengthened, and the 

 uterus in its increasing bulk extends backwards as well as forwards. 

 The cervix, firm and resisting, approaches the vulva, and to such a 

 degree sometimes that, in certain breeds of cattle — particularly those 

 which have the pelvis wide and inclined posteriorly, and bear large 

 calves — the posterior portion of the vagina appears between the labia 

 of the vulva a month or more before parturition, and especially w^hen 

 they lie down. 



With other Cows, however, whose abdomen is very pendant, the 

 opposite occurs ; for the uterus, in passing forwards and downwards, 

 carries the anterior portion of the vagina behind it, and this cavity 

 becomes lengthened and constricted posteriorly, while the cervix is 

 shortened, and the vulva appears to be deeply buried between the 

 tuberosities of the ischium. 



Directio)i. 



With regard to the direction of the uterus, it is to be noted that its 

 horizontal position in the domesticated animals obviates those lateral 

 displacements which are so frequent in woman — its weight, and that 

 of its contents, maintaining it in an antero-posterior direction, and in a 

 line with the body of the animal. This direction rarely varies to any 

 appreciable degree, and it is only in a case of hernia at the flank, which 

 is very uncommon, that it inclines to one side. The only marked 

 inclination it assumes is forward and downward in Cows, whose 

 abdomen is very wide and pendulous. Otherwise, the uterus keeps its 

 normal direction. Eainard draws attention to a form of abdominal 

 hernia which gives the uterus a particular direction ; it is that which 

 takes place in the Mare or Cow, in the vicinity of the crural arch, when 

 the uterus, or one of its horns containing the foetus, descends behind 

 the corresponding mammary gland, or into the subcutaneous connective 

 tissue of the inguinal region, forming a large tumour in which the limbs 

 of the young animal can be felt. 



Another change in the direction of the uterus, which it is most 



