Hard Free Body in the Carpal Portion of a Race Horse

Abstract

A joint mous and chip fracture of the radius were found in the anterior surface of the left carpal joint of a race horse. There was a joint mous in the carpometacarpal portion (third carpal bone-third metacarpal bone junction). The fracture of the radius was healing in a three-month period. The joint mous was studied radiographically and histopathologically in detail. Since the discovery of the joint mous, the horse had shown nosymptoms and often entered races for three years after the first clinical examination. Then the horse became lame on account of the joint mous, which was immediately removed from the carpal portion. It was a hard free body 1.5X1.0X1.0 cm in size and wedge-shaped. The radiographic appearance of the hard free body indicated that the body had been enlarged and derived from the soft free body. The results of histological examination of the hard free body revealed that there was histogenesis of long bone with enchondral ossification in the carpal joint. When the hard free body had been removed, the horse was recovered from lameness in two months and then able to race again.