432 



DISEASES OF THE HORSE'S FOOT 



the bone are accompanied by well-marked lesions on its 

 gliding or postero-inferior surface, and by evidences of an 

 osteoplastic periostitis along its edges. 



That an osteoplastic periostitis has been in existence is 



Fig. 



162. — A Foot with the Seat of Navicular Disease 

 Exposed. 



On the anterior surface of the performans fibres of the tendon are 

 seen to be torn away from their abnormal adhesion with the 

 navicular bone, while others are seen to be still attached there- 

 to. The surface of the navicular bone itself exhibits small de- 

 fects in the bony substance, which have been brought about by 

 a rarefactive ostitis. 



a, The performans tendon cut through and reflected ; b, the sole. 



witnessed by the appearance along the edges of the bone of 

 numerous outgrowths of bone, termed osteophytes (see 

 Fig. 163). 

 The interosseous and postero-lateral ligaments of the 



