DISLOCATION OF THE PATELLA. 315 



animals, especially if they are in a debilitated state, or are out 

 at grass on a rough and hilly country, the nature of which -would 

 predispose them to this injury, which, however, may take place, 

 as a result of accident, at any age. Young horses that suffer, off 

 and on, from this dislocation, often lose their liability to it with 

 ircreasing strength and age. 



Tlie dislocation may be complete or partial. In the former 

 instance, the patella is entirely removed from the pulley-like 

 portion of the femur, the two prominences of which can, then, 

 be felt with the hand under the skin. In the latter and much 

 more common case, it rests on the edge of the pulley, only one 

 prominence of which will be uncovered. In both, the unusual 

 position assumed by the patella will be manifest. When the 

 dislocation is complete, the affected limb is kept pointed to the. 

 rear, straight and stiff ; while the front of the wall of the hoof, 

 or, even, the front of the pastern, rests on the ground. The limb 

 is carried in the same manner, if the animal is made to walk, 

 which he naturally does with great difficulty. When the displace- 

 ment is partial, the lameness is similar to that just described, 

 although less in degree; and, if the horse is made to walk, the 

 patella may slip into and out of its position with a certain amount 

 of noise. Sometimes, both legs are affected, in which case, the 

 displacement is usually partial. 



When the dislocation is partial, it may become spontaneously 

 reduced, if the animal be startled by the crack of a whip for 

 instance, and made to move forward a few paces ; or the patella 

 may be pushed into its place with the hand, while the animal 

 tries to advance the limb. When such simple measures do not 

 suffice, or when the dislocation is complete, a rope should be 

 attached to the pastern of the injured limb, passed through a 

 collar (formed of rope, for instance) round the animal's neck, and 

 should be drawn forcibly forward. The. operator should then use 

 every effort to push the patella into its place ; while, to assist 

 him, the animal may be backed so as to force it to put weight 

 on the affected leg. If these methods fail, the horse should be 

 placed under the influence of chloroform, which will cause general 

 relaxation of the muscles. No time should be lost in reducing 

 the dislocation; for if this be not done, injurious changes will 

 quickly take place in the smooth surfaces of the joint in question. 

 When the patella has been replaced into its proper position, the 

 limb should be kept advanced by means of a side line fixed to 

 its pastern and passed round the neck as a collar. A long-toed 

 shoe (Fig. 104) will aid in keeping the stifle joint bent. The part 

 may be kept at rest and repair hastened by the application of one 

 flr tiyo smart panthwde^s ■ blisters.. A§ this accident is apt to 



