Pelvic Constriction 



677 



and movable sacro-iliac articulation on the other side, whenever 

 traction was applied, the pubis moved toward the sacrum and the 

 Channel closed like a cam. The fetus was dead. and the mare 

 was worthless, so that delivery by other means was ignored and 

 the animal was at once destroyed. 



d. Exostosis, as a result of dislocation of the femur 

 through the foramen ovale. Fig. 113 A illustrates the pelvis 

 of a cow, in our collection, in which there has been an old stand- 

 ing dislocation of the femur through the foramen ovale. As a 

 result of the constant irritation there has developed a large ex- 

 ostosis inside the pelvis, which would naturally cause serious 

 obstruction in case of parturition. Exostoses or bone tumors 

 may arise in the pelvic canal from various causes, and offer more 

 or less serious obstruction to birth. 



e. Eminences along the ischio-pubic symphysis, Fig. 

 113 B, are not rare in the pelvis of the mare. Their cause is 



Fig. 113B. Pelvis of Marb. 

 Showing prominent elevations, A, B and C on the anterior margin of 

 the pelvic inlet. 



