DISEASES OF BONES 155 



pieces of bone forcing themselves througi. the tissues ; or, 

 finally, the injury of the soft parts may be secondary, being 

 the result of necrosis from the pressure of displaced bony 

 fragments, rough handling, as an animal suddenly throwing 

 excessive weight upon the broken limb on account of slings 

 in which it rests or slipping, or the soft tissues injured during 

 the accident, slough. This variety of fracture is always 

 serious, mainly on account of the possibility of infectious 

 complications, as tetanus, septicaemia, necrosis. 



Transverse displacement : There is a complete or partial 

 dislocation of the fragments at a right angle to their former 

 normal long axis ; that is, one fragment is either in front, 

 T)ehind or back of the other one, but they do not overlap each 

 other. 



Angular displacement : The fragments are dislocated at 

 an oblique angle to their normal long axis ; that is, the frag- 

 ments form an angle with each other. 



Rotary displacement : One or the other fragment - is 

 turned about its normal long axis. 



Over-riding displacement : The broken surfaces overlap 

 each other, thus bringing the two extremities of the broken 

 bone more closely together. 



Impaction displacement : The bone is shortened as the 

 fragments are forced into each other. 



Direct longitudinal separation : The broken parts are 

 •drawn apart in a longitudinal direction. 



, Which animals furnish the most fractv/res ? 



In the large cities, with their ashphalt pavement, street 

 <3ar rails, slippery roads in winter, fractures in the horse are 

 common; otherwise, kicks, running against solid objects, 

 casting the animal, etc., are frequent causes. Next in fre- 

 quency comes the dog ; here bites, blows, falls and being run 



