298 DISEASES OF THE HORSE. 



it becomes compound if the soft parts have suffered laceration, and 

 comminuted if the bone^ have been crushed or ground into fragments, 

 many or few. The direction of the break also determines its further 

 classification. Broken at a right angle it is transverse ; at a different 

 angle it becomes ohlique^ and it may be longitudinal^ or lengthwise. 

 In a complete fracture, especially of the oblique kind, there is a con- 

 dition of great importance in respect to its effect upon the ultimate 

 result of the treatment in the fact that from various causes, such as 

 muscular contractions or excessive motion, the bony fragments do 

 not maintain their mutual coajjtation, but become separated at the 

 ends, which makes it necessary to add another descriptive term — with 

 displacement. And these words again suggest the negative, and 

 introduce the term without displacement., when the facts justify that 

 description. Furthermore, a fracture may be intra-artlcular or extra- 

 articidai\ as it extends into a joint or otherwise, and once more, intra- 

 penosteal., when the periosteum remains intact. Finally, there is no 

 absolute limit to the use of descriptive terminology in the case. 



The condition of displacement is largely influential in determining 

 the question of treatment and as affecting the final result of a case of 

 fracture. This, however, is dependent upon its location or whether 

 its seat be in one or more of the axes of the bone, in its length, its 

 breadth, its thickness, or its circumference. An incomplete fracture 

 may also be either simple or comminuted. In the latter case the frag- 

 ments are held together by the periosteum when it is intact, and the 

 fracture in that case belongs to the intraperiosteal class. At times, 

 also, there is only a simple fissure or split in the bone, making a con- 

 dition of much difficuhy of diagnosis. 



Causes. — Two varieties of originating cause may be recognized in 

 cases of fracture. They are the predisposing and the occasional. As 

 to the first, different species of animals differ in the degree of their 

 liability. That of the dog is greater than that of the horse, and in 

 horses the various questions of age, the mode of labor, the season of 

 the year, the portion of the body most exposed, and the existence of 

 ailments, local and general, are all to be taken into account. 



Among horses, those employed in heavy draft work or that are 

 driven over bad roads are more ex^^osed than light-draft or saddle 

 horses, and animals of different ages are not equally liable. Dogs 

 and young horses, with those which have become sufficiently aged for 

 their bones to have acquired an enhanced degree of frangibility, are 

 more liable than those which have not exceeded the time of their 

 adult i^rime. The season of the year is undoubtedly, though in an 

 incidental way, an important factor in the problem of the etiology of 

 these accidents, for though they may be observed at all times, it is 

 during the months when the slippery condition of the icy roads ren- 

 ders it difficult for both men and beasts to keep their feet that they 



