68 LAMENESS IN THE HORSE. 



now and then seen ou the lateral aspect of the joint on one 

 or both legs, causing no lameness whatsoever, and some 

 skill is necessary to differentiate this condition from 

 enlargements consequent upon chronic arthritis, as seen in 

 sesamoid lameness. Whenever there is any doubt, sesamoid 

 lameness may be diagnosed, if diseased conditions of the 

 flexor tendons and chronic navicular disease are wanting. 

 The examination of the sound leg should never be omitted, 

 to compare results. 



5.— Fracture of the Sesamoid Bones. 



History. — Instantaneous lameness following galloping, 

 jumping and sudden work after continued rebt. 



Inspection. — Horizontal fracture of the sesamoid bones 

 shows severe supporting-leg lameness, with excessive dorsal 

 flexion of the fetlock joint ; later on, swelling of that region. 



Palpation. — In recent cases a depression may be felt 

 between the broken pieces, with great pain on pressure. 

 Crepitation is occasionally detected. 



Differential Diagnosis. — Rupture of the suspensory 

 ligament, perforans and perforatus, offer somewhat similar 

 symptoms, but are differentiated from fracture of the 

 sesamoid bones as follows : 



In rupture of the suspensory ligament the torn ends can 

 be felt, and the lameness is not so intense, nor the pain so 

 great on palpation, as in fracture of the sesamoid bones. 

 Rupture of the perforans and perforatus tendons is followed 

 by excessive dorsal flexion of the fetlock, the toe of the hoof 

 not touching the ground. In fracture of the sesamoid bones, 

 particularly in horizontal fractures, there is only dorsal 

 flexion of the fetlock, while the position of the hoof is normal 

 — that is, the toe is on the ground and not elevated, as in 

 rupture of the perforans, for instance. 



