176 NON-SPECIFIC OR GENERAL DISEASES 



from imperfect development of the external lip of the trochlea. 

 Such a deformity subjects the animal to frequent luxations. 



The symptoms may vary. The displacement may be first 

 noticed when the horse is backed out of the stall or turned 

 quickly. A slight " hitch " in the movement of the limb is noted, 

 that is followed by more noticeable flexion of the hock than 

 normal. In case the luxation is more permanent, the horse 

 stands quietly with the affected leg held stiffly and extended 

 backward. When made to move forward, it hops on the well leg 

 and carries the affected one, or drags it on the toe. If both limbs 

 are affected, the animal is unable to move. The inability to 

 move the limb is due to the patella resting on the external lip 

 of the pulley surface, and a locking of the stifle- and hock-joint. 



This accident is annoying, and in case the horse is subject 

 to it should be considered an unsoundness. 



The following treaiment may be recommended: The luxation 

 may be reduced in the large majority of cases by backing or 

 turning the animal. If this does not reduce the displacement, 

 a collar should be placed on the animal, and a hobble strap 

 fastened to the pastern of the involved limb. One end of a long 

 rope is tied to the collar, passed backward between the front 

 limbs, through a ring in the hobble and back over the outside of 

 the shoulder and under the collar. While an attendant pulls 

 the limb a little forward with the rope, the operator takes hold 

 of the foot and attempts to flex the limb, at the same time pushing 

 inward on the patella. After reducing the luxation it is advisable 

 to tie the rojDC to the collar, so that the limb is carried forward. 

 This prevents the animal from throwing weight on the foot. 

 It may be advisable to tie the animal so that it can not lie down, 

 if the foot is to be left hobbled for a few days. A fly blister 

 should be applied to the front and outside of the stifle and the 

 application repeated in two or three weeks. 



String-halt. — This term is applied to a peculiar involuntary 

 movement of one or both hind limbs that is characterized by a 



