LAMENESS IN THE HIND-LEG. 83 



outward luxation of the patella produces abnormal flexion 

 of the stifle joint ; upward luxation of the patella causes 

 excessive extension of both the stifle and hock joints. 

 Bupture of the-gastrocnemii or their tendons gives rise to 

 abnormal extension of the stifle and the hock joint, flexing 

 as weight is put upon the leg. 



3. Hock joint. Paralysis of the tibial nerve, which is 

 rare, produces excessive flexion of this joint in the swinging 

 as well as in the supporting leg ; abnormal extension of the 

 hock joint, as in rupture of the flexor metatarsi, fractures of 

 the femur and tibia. 



4. Phalanges. Paralysis of the tibial nerve and rupture 

 of the extensor pedis, especially its tendon, is manifested by 

 volar flexion of that region. 



Supporting-leg lameness of the hind-leg can be divided 

 into eight main groups. 



The supporting action of the hind-leg depends on the 

 resistance offered by its long bones and the fixing of the 

 different joints, which is mainly done by the triceps femoris 

 . and the tendon of the gastrocnemii. 



Suspension of the function of the supporting leg, with 

 inability to support the weight of the body, collapsing in 

 the attempt, is present in : 



1. Paralysis of the triceps femoris, or crural nerve. 



2. Animals suffering with thrombosis of the iliac arteries 

 after active exercise. 



3. Knpture of the patellar muscles and of the straight 

 ligaments of the patella. 



4. Complete outward luxation of the patella. 



5. Kupture of the gastrocnemii or their tendon. 



6. Fracture of the long bones. 



