SPRAIN OF THE PATELLAR LIGAMENTS. 285 



hop on the sound limb, keeping the affected one elevated 

 from the ground for a step or two, after which he 

 will allow it to descend to the ground, and again trot oft' on 

 it. There is much greater difficulty in bringing the limb 

 forward than there is in hip-joint or hock lameness. On 

 comparison of the affected joint with the sound one of the 

 opposite side, it is discovered that there is a peculiar and 

 unnatural prominence of the former ; in some cases there 

 seems to be as much difficulty in using the limb as though 

 the patella had become dislocated. Every endeavour of the 

 animal, whether being exercised or standing still, seems to 

 be directed to flexing or using the joint in any way as little 

 as possible. Negative symptoms, or the absence of disease 

 in any other part of the limb, will often be of great assist- 

 ance in arriving at a correct diagnosis. Professor Dick used 

 to tell his pupils to examine the foot, although the leg was 

 broken ; and the advice was very good, as a thorough ex- 

 amination will not often result in a mistaken diagnosis. 



Treatment. — The sooner such a case is treated the better. 

 Hot or cold applications are to be used, according as to 

 whether the weather is warm or cold, after which a vesicant 

 should be applied, so as to invest a considerable surface, and 

 the animal should be allowed a long rest. 



Dislocation of the Patella. — It is seldom that complete dis- 

 location of the patella takes place, because complete rupture 

 of the internal lateral ligament would first have to occur. 

 Partial dislocation, however, is of very common occurrence, 

 the bone slipping to the outside in all cases ; it being on 

 account of the structure of the parts almost an impossibility 

 for the bone to slip to the inside. 



Causes. — Dislocation of the patella may be caused by fall- 

 ing, slipping, stepping on a cobble stone, or a stone that 

 rolls or gives way, particularly if the animal is trotting. It 

 is also sometimes observed to follow debilitating diseases, as 



