IX. 

 FRACTURES OF BONES. 



A fracture may occur in three ways — first, by external vio- 

 lence, operating- directly upon the injured part; second, by exter- 

 nal violence, producing such concussion upon the bone as not to 

 break it where the force is applied, but at some other part; third, 

 by inordinate action of the muscles, as in broken back. Some 

 bones are more liable to fracture than others. The bones of the 

 pelvis, shoulders, thighs, pasterns, and vertebrae seem to be more 

 frequently broken than others. Bones in a diseased condition 

 are liable to fracture from trivial causes. The bones of old 

 horses are more readily broken than those of the young. 



A solution of continuity of bone (fracture) may be transverse, 

 oblique, or longitudinal, according as it is at a right or an acute 

 angle with, or parallel to, the long axis of the part of the bone 

 in which it is situated. There are several varieties of fractures, 

 known as simple, compound, comminuted, and complicated. A 

 fracture is said to be simple, when a bone is broken at one part, 

 without any injury of soft parts; compovnd or open, when the 

 broken ends separate, pierce the soft tissues, and injure the skin; 

 comminuted, when the bone is broken into several fragments; 

 complicated, when, together with the fracture, there is a serious 

 injury to the joining structures, as laceration of blood vessels, 

 nerves, open joint or serious contusion of the tissues. There 

 may be fractures without displacement, as sometimes happens 

 when the tibia of the horse is fractured and held in place by the 

 periosteum for days or weeks, without displacement, the frac- 

 tured ends of the bone being held in apposition until complete 

 reunion takes place. 



An erroneous idea has prevailed among horsemen that frac- 

 tured bones in the horse will not unite as quickly as the bones of 



(144) 



