104 



PARTICULAR FRACTURES. 



lower jaw, or the inferior maxillary division of the fifth nerve 

 may be injured and pressed open by a piece of depressed bone, 

 causing excruciating pain, and even fatal results, if not at once 

 removed. 



FRACTURES OF THE CRANIAL BONES. 



By the arrangement of the cranial bones, an ovate box is 

 formed, which resists external violence after the manner of an 

 arch ; yet it is sometimes fractured by the direct application 



of force to the fractured parts, but 

 more frequently — in the lower ani- 

 mals, especially in the horse — at a 

 part of the skull distant from the 

 place where the violence has been 

 received. This is called "indirect 

 frachtre" or fracture hy counter- 

 stroke, or what is termed by the 

 French, fracture par contre-coup. 



Fractures of the base of the skull 

 are, in all instances, caused by the 

 indirect application of violence, and 

 this is easily explained. If a horse 

 fall, or be struck heavily by a blunt 

 instrument or obtuse body, upon the 

 occipital crest, the force thus applied 

 is resisted by the strength and thick- 

 ness of this part of the bone, and the 

 shock is conveyed to the basilar 

 process, this being its weakest part. 

 In all cases this form of fracture 

 Fig. 11 —Indirect comminuted fg necessarily fatal. 



fracture of basilar process of occi- _, . , . , 



pitai and sphenoidal bones, from Sometimes the Violence ot the 

 falling on occipital crest, a, Occi- faU or blow is Sufficient to producc 



pitaL b, Sphenoid. ^ • -, ■ 



fracture of the part to which it is 

 applied, and also to extend to the base of the cranium. 



The fractures of the cranium may be conveniently arranged 

 as follows : — 



\st. Simple fissure or fracture without depression. 



2d. Simple fractures with depression. 



