326 DISEASES OF THE ORGANS OF LOCOMOTION 



larly the bones of the extremities, femur, radius, tilna and filuila, uhia 

 and humerus and metacarpus and pelvis being the commonest, less 

 frequently seen are the metatarsus; the sternum, ribs, cranium, vertebrae, 

 and scapula are very rarelj' seen. 



Etiology and Prognosis. — IMost fractures are caused by external 

 forces, and the bone fractured is at the region where the force or shock 

 has expended most of its force — for instance, from blows or being run 

 over, hit with a stone, or in some instances a fracture may be some 

 distance from the region where the greatest amount of force has been 

 made, such as falling for some distance, or concussions. We also see 

 fractures of small projections of bones caused Ijy great muscular exertion. 

 Very old and very young dogs have a predisposition to fractures and 

 rickets, or a tendency that way may also produce fractures from a 

 weakened or softened condition of the bone. 



We separate fractures under different names according to their 

 position, severity, and the complications accompanying them. 



In the first class belong infractions, splits or cracks, impressions or 

 depressions. 



In the second class belong obliciue, transverse, longitudinal, and 

 fissure fractures. 



In pups the epiphysis and diaphysis are sometimes fractured through 

 the symphysis, due to traumatic influences. This fracture, which is 

 rather common, especially in the humerus and radius, is always confined 

 to the immediate neighborhood of the symphysis. The general course 

 of these fractures is the same as ordinary fractures, and no special men- 

 tion is necessary regarding fractures of the soft bone, which in the young 

 animal has not yet hardened. 



The condition of the soft tissues in the neighborhood of the fractures 

 and the amount of injury that they have had are of great importance 

 in the prognosis. All fractures in which the soft tissues are not very 

 much injured, and where the skin has not been torn, heal very much more 

 quickly than those where there is an open wound extending into the 

 fractured end of the lione. The first are termed simple fractures, and 

 the latter, compound fractures. Where the fracture has involved a joint, 

 it is called an intra-articular fracture. The compound and intra-articular 

 fractures are very slow and difficult to treat, and present such symptoms 

 as synovitis, either with or without serous or purulent inflammations. 

 In such fractures, even when we have union of the broken ends of the 

 bone we may have as an after result a stiff joint or ankylosis from com- 

 plications in the joint. 



Clinical Symptoms. — The symptoms of fractures are generally 

 indicated by partial or complete loss of the use of the whole or part of a 

 limb. There is pain on pressure, deformity in the symmetry of the broken 



