The Pelvis 9 



the ischial tuberosities so small and wide apart as to be of little 

 significance. 



The measurements of the pelvic cavitj' vary wideh^ in different 

 species, breeds and individuals so that it is virtually impossible 

 to make any general statements as to the dimensions of the 

 pelves of our domestic animals. The variations in size among 

 domestic animals are extreme, owing to artificial selection for 

 the production of giant and dwarf animals, which are widely sep- 

 arated in stature. In the horse it is not rare to find animals 

 weighing 250 lbs. or 2500 lbs., or a ratio of 1:10, and there is 

 naturally a corresponding variation in the measurements of the 

 pelvic passages. In the dog the variations are even greater in 

 size, the ratio in weight being at times as great as 1:100. It is, 

 therefore, quite impossible to give a rea.sonably approximate 

 measurement of the pelves of the different species of domestic 

 animals. The most important diameters of the pelvis of the 

 mare to be considered by the veterinarian are the supero-inferior, 

 extending from the lumbo-sacral articulation to the anterior 

 point of the pubic symphysis ; a vertical diameter of the inlet 

 from the symph)'sis pubis to the middle of the sacrum ; and a 

 transverse from the most concave point of one ilium to the corre- 

 sponding point on the opposite side. For the outlet, usually but 

 two diameters are considered ; a vertical, from the ischio-pubic 

 symphysis to the sacro-coccygeal articulation and a transverse, 

 from one ischial tuberosity to the other. The measurements 

 vary considerably in the experiences of different authors, the 

 supero-inferior for an average horse being 9 to 10 inches accord- 

 ing to Baumeister & Rueff ; 9.5 by Carsten- Harms ; 9 by Ar- 

 loing and 8.75 by Saint-Cyr. The same authors make the trans- 

 verse diameters 1 1 to 12.5; 9.2; 9.2 and 8.1 in. respectively. 

 These authors have evidently secured their measurements from 

 different classes of mares. 



In the cow, the average diameters of the pelvic inlet as given 

 by various authors range between 8^ and 10^2 inches trans- 

 versely and 6^ to 7^ perpendicularly, with an outlet somewhat 

 smaller in each of its measurements. 



The ewe and she-goat show a perpendicular diameter of the 

 pelvis averaging about 4,7 in. and a transverse measurement of 

 approximately 3.1 in. The bitch shows a very wide variation in 

 pelvic measurements, ranging from 2 to 2 1-3 in. in the sacro- 



