In Figures 17 and 18 there are large fractures of the extensor process of P3 with significant articular involvement. In evaluating the significance of calcifications of the extensor process, the degree of articular involvement and radiographic evidence of concurrent degenerative joint changes in the area are important. I am optimistic about a horse's future usefulness if he has a small calcified or ossified area of the extensor process with little, if any, articular involvement and no radiographic evidence of degenerative joint changes. However, if there is articular involvement (Figs. 17 and 18) and/or degenerative changes involving the distal interphalangeal articulation (Fig. 16), I would be pessimistic about the horse's future soundness. Careful evaluation of the distal interphalangeal joint, in the lateral, dorsoventral, and anteroposterior radiographs, will enable one to determine if a separate center of ossification is old and inactive or is associated with significant articular involvement and/or degenerative joint changes.
|Figure 17.||Figure 18.|
|Lateral radiograph of the foot demonstrating a separate ossification center or old chip fracture of the extensor process of P3 with significant articular involvement of the third phalanx.||Lateral radiograph of the foot demonstrating separate ossification center or old fracture of the third phalanx with significant articular involvement.|