CAUSES AND PROGNOSIS OF SIDE BONE. 



405 



greater shock during movement, explains why the outer 

 cartilage more frequently becomes ossified than the inner. 



The prognosis depends on the horse's work, weight, and 

 breed, on the form of the hoof, and on the extent of ossifica- 

 tion. Heavy horses with completely ossified lateral cartilages 

 are of little use for rapid work on paved streets. When only 

 one cartilage is affected, or when the animal is worked on soft 

 ground, side bones are comparatively unimportant. Whilp 



Fig. 383.— Right fore-foot altered in form in 

 consequence of side bone. 



Fig. 384.— Shoe for above foot, with broad 

 outer hmb. 



ossification is in active progress the animal goes tender, if not 

 actually lame, but as soon as it becomes complete the lameness 

 tends to disappear, though it readily returns in consequence of 

 bruising or strain if the tread is not level. Lameness is 

 usually temporary, but the diseased cartilage can never be 

 restored to its primitive condition. 



After ossification is complete, lameness may be produced by 

 bruising of the plantar cushion and of the sensitive wall, which 

 are then enclosed between two hard, unyielding structures ; 

 the plantar cushion, being confined by the ossified cartilages, 

 can expand neither towards the right nor left at the moment 

 at which weight is placed on the foot and the sensitive wall 

 being similarly placed between the horny wall and ossified 

 cartilage. A partial improvement may occur when the plantar 

 cushion diminishes in volume. If, in addition, the wall is 

 contracted at the heels, the condition is even more serious. 



