bones: diseases and accidents. 277 



tion. The bones of some animals are more easily fractured than those 

 of others, owing to certain predisposing causes, such as age, habit, or 

 hereditary constitutional weakness. The bones of an animal ad- 

 vanced in years are more subject to fracture because of the preponder- 

 ance of inorganic matter rendering them more brittle. They are also 

 occasionally rendered liable to fracture by a previoush^ existing 

 diseased condition. Fractures are divided into four clabses — partial, 

 simple, compound, and comminuted. 



PARTIAL FBACTTJBES. 



Partial fractures are those which are likely to occur in a young 

 animal in which the preponderance of animal matter or the semicarti- 

 laginous condition of the bone renders it tough, so that even when 

 considerable force is applied the bone bends, breaking on the side 

 opposite that to which the force was applied, after the manner in 

 which a green stick would bend and break. 



SIMPLE FRACTURES. 



Simple fracture is one in which the bone is severed in two parts, 

 either transversely, longitudinally, or obliquely, without serious in- 

 jury to the adjoining structures. 



COMPOUND FBACTUBES. 



Compound fracture is one in which there is an open wound per- 

 mitting the air to communicate with the ends of the broken bones. 



COMMINUTED FBACTUBES. 



Comminuted fracture is one in which the bone is shattered or 

 divided into a number of fragments. 



COMPLICATED FBACTUBES. 



Complicated fracture is one where other structures surrounding 

 the bones are injured. 



GENERAL SYMPTOMS OF FRACTURE. 



TVlien a fracture of one or more of the large bones of a limb occurs, 

 symptoms are sure to be well marked. After the accident the animal 

 refuses to touch the foot to the ground and, if compelled to move, 

 does so with great pain and reluctance. There is more or less short- 

 ening of the limb, with trembling of the muscles in the vicinity of 

 the injury: deformity, and increased mobility, so that, instead of the 

 natural joints of the limb and the natural muscular control of their 



