lo Veterinary Obstetrics 



pubic and i.2 to 2 in. in the transverse diameter. Similar varia- 

 tions occur in the measurements taken by the various observers 

 of the other diameters of the pelvis of the mare and of other ani- 

 mals, the differences being so wide as to render the measurements 

 of questionable value. Some investigators have attempted to 

 establish rules for determining approximately th.e diameters of 

 the pelves of living animals, but, thus far, have been unable to 

 turn pelvimetry to practical account in veterinary obstetrics, in 

 contrast with human practice, where it acquires fundamental im- 

 portance on account of the frequency' of pelvic deformities, which 

 often render normal parturition impossible. These deformities 

 rarely occur in our domestic animals, partly because the osseous 

 system is far more mature at birth than is observed in man and 

 still more because a pelvis weakened by disease is subjected to 

 no such strain in quadrupeds. The horse bears only 45 % of his 

 total weight upon his posterior feet and this is largely made up 

 by the weight of the limbs themselves and the muscles connect- 

 ing them with the trunk so that the actual weight resting upon 

 the pelvis in domestic animals is inconsequential and represents 

 probably less than 25 % of the total body weight, while, in man, 

 it needs endure the entire body weig^ht, except the legs themselves. 



The pelves of domesticated animals are sometimes seriously 

 deformed as a result of fractures, tumors and dislocations, which 

 may render parturition difficult or impossible. 



Pelvimetry in domestic animals is impracticable usually in the 

 two chief groups of cases where the size of the pelvis has to do 

 with dystocia. When the pelvis is deformed as a result of tu- 

 mors, fractures, dislocations or rickets, the constriction is rarely 

 recognized until the veterinarian is called because of dystocia 

 and he faces the question of overcoming it and must determine 

 his method of procedure by a rough comparison of the size of the 

 fetus as related to the capacity of the pelvis, as estimated by man- 

 ual exploration. He is then in a position to advise the owner in 

 reference to the future of the patient, whether she should be 

 again used for breeding purposes, turned to some other available 

 use, or destroyed. When dealing with such injuries in non-preg- 

 nant animals, it is clearly the duty of the attending veterinarian 

 to warn the owner against breeding the animal unless careful 

 examination makes it clear that the patient may normally give 

 birth to young. 



