FRACTURES OP THE PHALANGES. 869 



side of the bone. In most cases the fissure runs towards the outer 

 side — a fact perhaps due to the smaller size of the outer division 

 of the articular surface. During this examination the limb must 

 of course be at rest, otherwise it would be impossible properly to 

 estimate the degree of local pain. It is only after the lapse of some 

 time that periostitis or exostosis can be detected at the upper end 

 of the bone. 



In solipeds fractures of the os coronae are caused in the same 

 way as those of the os suffraginis. They are a common sequel of 

 the foot being caught between railway-metals. The bone is either 

 split longitudinally or may be broken into several fragments. Henon 

 saw the os coronse broken into seven, Schrader into six, and Lafosse 

 into twenty pieces. Henon saw a horse with fracture of the os coronse 

 in all four feet ; sometimes only the ligamentous prominences are 

 torn away. Moller mentions a case in which the bone was fractured 

 into a number of pieces by a nail penetrating through the frog. 

 Fissure and simple fracture are less common in this bone than in 

 the os suffraginis. 



Fracture is detected in the same way as in the suffraginis, and 

 even when complete offers considerable difficulty. Crepitation in 

 this region points to fracture of the os corona?, provided the suffraginis 

 is known to be intact. 



Fracture of the os pedis is comparatively rare, though it has been 

 seen by a number of observers. It is caused in the same way as 

 fracture of the other phalanges, i.e., by slips, particularly when 

 animals are suddenly reined-up ; but fracture of the pedal bone 

 also follows injury by picked-up nails. Fracture is common in 

 horses which have been kt unnerved." In this case its occurrence 

 is partly explained by loss of sensation in the foot producing abnormal 

 action, partly by alteration in the nutrition of the foot and changes 

 in the bone. It is well known that after chronic lameness the 

 nutrition of the bones of the affected limb generally suffers. 

 According to Williams, fracture also results from the heels of the shoe 

 being caught in railway-points, and, in heavy horses, from falls. 

 Lemhofer saw fissure of the os pedis produced by the horse striking 

 the foot againt a wall when jumping. This fracture united in four 

 months, Schrader also noted fractures of the ossified lateral cartilage. 



Diagnosis is very difficult, crepitation being rare. Only occasion- 

 ally can it be produced by rotating the foot or pressing the heels 

 together, and in its absence the diagnosis must be arrived at by a 

 process of elimination, and by considering the history. Fracture 

 of the os pedis may be surmised when severe pain is shown on attempts 



