98 LAMENESS IN THE HORSE. 



Inspection {incomplete paralysis). — The posterior half of 

 the step is shortened, all joints are somewhat flexed, and 

 the croup of the aflfected side sinks down a little. In older 

 cases, the animal accustoms himself to a peculiar gait, seen 

 to advantage when the horse is led slowly by the observer. 

 The animal makes use of the abductor and adductor muscles 

 of the leg to aid immobilizing the stifle joint, as the triceps 

 femoris is powerless. The superior extremity of the tibia 

 is drawn up and backwards, and the patella remains fixed 

 on the condyles of the femur. 



Differential Diagnosis.— '^n'^iwre of the muscles of the 

 triceps femoris and outward luxation of the patella give rise 

 to similar symptoms. The diagnosis of the former is very 

 difficult ; a gap may possibly be found between the separated 

 ends of the muscles. The fact that crural nerve paralysis is 

 usually a sequel to haemoglobinsemia and that rupture of 

 the muscles follows falls or slips, etc., may facilitate the 

 diagnosis of rupture of a muscle. Outward luxation of the 

 patella is recognized by careful palpation. 



4. — Incomplete Paralysis of the Hind-leg. 



^^'.s^or?/.— Lameness following exposure to wet and cold, 

 unaccustomed hard and continued work, and struggling when 

 cast and unable to rise, etc. 



Inspection. — Loss of strength and irregularity of movement 

 are apparent. Such animals appear weak behind and tire 

 rapidly. The feet are raised incompletely, the toes are 

 dragged, and the corresponding part of the horny box is 

 worn excessively. The animal finishes the step by lifting 

 the feet up rather suddenly and carrying them to an abnormal 

 height; quite frequently the leg makes a swinging outward 

 movement as it advances. In the next step the horse takes, 



