IIG LAMENESS IN THE HORSE. 



observed. To locate a curb, the hock is viewed from the 

 side. lustead of a straight line from the point of the os 

 calcis to the fetlock, a convex downward swelling, three to 

 four inches below the point of the os calcis, is seen. 



Differential Diagnosis. — Abnormal thickness of the skin 

 in that direction may lead to errors ; but here the skin is 

 movable, while in curb the swelling is stationary. Enlarge- 

 ment of the reinforcing ligament of the perforans tendon 

 generally extends further down the tendon, thus differing 

 from curb. The so-called bony curb is really a spavin, 

 situated in that region, almost invariably accompanied by 

 exostoses on the inner surface of the hock joint. 



6.— liuxation of the Flexor Pedis Perforatus Tendon. 



History. — Sudden lameness when pulling a heavy load, 

 and external violence. 



Inspection. — In the standing posture the phalanges show 

 abnormal dorsal flexion, but the hock joint is extended. 

 The slight lameness and tottering, unsteady gait are strik- 

 ing. Whenever an attempt is made to extend the hock, it 

 will be seen that the perforatus tendon slips off the point 

 of the OS calcis, usually gliding back into its place as soon 

 as the leg is flexed. Swelling of that region and lameness are 

 pronounced, especially when the luxation is the result of an 

 external injury, such as a kick. 



Palpation. — Unless swelling, which is hot and painful, is 

 severe, the perforatus tendon can be felt in its abnormal 

 position. 



