35^ Surgical Diseases and Surgery of the Dog 



Symptoms and Diagnosis. At first the animal may walk on 

 three legs but later gains imperfect control of the injured member. 

 A swelling is observed over the joint, the trochanter has become 

 prominent, and the leg appears shorter than its fellow. In displace- 

 ment into the foramen ovale the leg appears longer than its fellow. 

 When the animal walks, the stifle is turned outward and a certain 

 swinging motion is evident. The prognosis is excellent provided re- 

 duction is effected soon after the accident. If the luxation is neg- 

 lected a false joint is formed through development of a new capsular 

 ligament from the surrounding cellular tissue, and the movements be- 

 come comparatively free, though the leg is dragged somewhat. The 

 longest period intervening between receipt of the injury and treat- 

 ment in my hands which turned out satisfactorily was two weeks. 

 Stockfleth found a false joint completely formed with a thick flask- 

 shaped capsule two months after the dislocation had occurred, and 

 Peuch failed to effect reduction in a dislocation of one month's 

 standing. 



Treatment. The leg must be forcibly extended by traction and 

 abducted, downward pressure being at the same time applied over 

 the trochanter. 



The Patella. In the dog, the lateral patellar ligaments are 

 little more than rudimentary, while the middle one is well-developed. 

 Consequently the patella is very liable to become displaced either 

 to the inner or outer aspect of the joint, but as a rule to the inner. 

 The chief factor concerned in the occurrence of this luxation is 

 relaxation of the feebly-developed lateral ligaments, coupled with 

 a feebly developed internal ridge of the patellar groove of the femur, 

 and to complete the lesion it is only necessary for a violent or exces- 

 sive contraction of the tendon of the quadriceps femoris muscle to 

 take place, particularly in conjunction with inward or outward 

 turning motion of the lower part of the legs as, for instance, when 

 a dog jumps up and through a window. Toy breeds, such as the 

 Black-and-Tan Terrier and Japanese Spaniel suffer most, and it is in 

 these that we find the internal femoral ridge lacking in development. 

 The displaced bone is easily replaced when the whole leg is in an ex- 

 tended position forward but shows a great tendency to revert to the 

 abnormal position upon flexion. 



Symptoms and Diagnosis. This luxation is characterized by 

 a peculiar carriage of the affected leg. The latter can no longer 



