58 



Journal of Agriculture. 



[8 Jan., 1908. 



Fracture bv indirect violence occurs when the fracturing force is 

 applied at a part remote from the seat of fracture — when the violence 

 sustained is transmitted by concussion and produces its effect b\ counter 

 shock at some distance from the seat of direct injury. The most frequently 

 met with example of this is fracture of the basi-occiput or basi-sphenoid at 

 the base of the brain from violence applied tO' the poll (crest of the occiput) 

 (see Fig. i), such as may occur when a horse rears and throws himself 

 backwards on the back of his head or when he " somersaults " over a fence 

 and strikes the ground with the poll. 



As an instance of fracture resulting from the inordinate application 

 of muscular power the breaking of the bones of the back (vertebrge) occur- 

 ring during the struggling of horses when cast for operations, may be 

 cited. 



Kinds of Fracture. — Fractures var\ in character and degree of 

 gravity, and for descriptive purposes thev are classified as follows: — 



I. Simple Fracture in which the break is single and the soft struc- 

 tures surrounding are uninjured. Such fractures may occur either with 

 or without displacement of the broken surfaces. In the latter case the 

 broken ends of bone are usuallv maintained in position by the periosteum — 

 the strong fibrous covering of bone — and in such cases the repair of the 

 fracture, or knitting of the broken bones, takes iplace quickly. Fracture 

 without displacement also occurs when a bone (the tihia for instance) is 

 split lengthways and only ])artially across, thus: — 



Fig. 2. Sketch of partial fracture of a lonj^ bone (the tibia) without displacement 

 of the fractured ends — otherwise called a " jj-reen-stick '' fracture. 



Such a fracture is often called a " green-stick " fracture on account 

 of its resemblance to the partial breaking of sappy wood. 



2. Comminuted fracture in which the the bone is broken into several 

 pieces. (See Fig. 3.) 



!■ 'K- 3- Comminuted fracture of the arm bone of the horse (the humerus). 

 Frequently the fragments into which the bone is broken in a comminuted fracture are 

 much more numerous. _(After Dollar.) 



3. Compound fracture when, accompanying the fracture, there is an 

 external wound communicating with it. 



4. Compound-comminuted fracture when there is an external wound 

 ■communicating with a fragmentary fracture. 



