FRACTURES OF THE PASTERN BONES 69 



FRACTURES OF THE PASTERN BONES 



In these cases the first or second phalanges, or both, may be involved. 

 Most commonly, however, the fracture is confined to the os suffraginis. 



Such fractures may be simple rents, or fissures, disposed transversely 

 or longitudinally, or the bone may be broken into many pieces, and the 

 fracture be even compound. They are commonly met with in race- 

 horses, as a result of turning suddenly, slipping or taking a false step, and 

 in steeplechasers when jumping. But fracture of the pastern bone may 

 occur without any special apparent cause, quite independently of any 

 strenuous exertion or accident, and even comminuted fractures have been 

 known to occur during the performance of ordinary and gentle work on 

 the level. Such fractures as occur without any special cause being 

 apparent are sometimes termed spontaneous fractures. 



Fracture ot the second phalanx is said to be due frequently to the 

 foot being caught between railway metals. 



The symptoms presented are not very characteristic. The animal 

 falls suddenly lame and hops. If the fracture be comminuted there is 

 crepitation [Williams had a case in which the os suffraginis was broken 

 into over 100 pieces]. Occasionally pieces of bone project through 

 the skin. The cases which present the greatest amount of difficulty in 

 diagnosis are those in which the pastern bone is simply split longi- 

 tudinally into two portions, and there is no displacement. 



Lameness is severe, and if the foot be taken up and the part carefully 

 felt with the tips of the fingers in the longitudinal direction, there will 

 be marked flinching as the line of the fracture is traced out. 



This line, as Peters pointed out, usually commences in the antero- 

 posterior groove on the superior aspect of the bone, and it may extend 

 vertically, or obliquely downwards and outwards, or downwards and 



inwards. 



In ten to fourteen days the swelling may be readily distinguished 



