310 OPERATIONS ON MUSCLES AND THEIK ANNEXES. 



The symptoms characteristic of this lesiou are readily identi- 

 fied. Principally, there is great difficulty in flexing the hip joint. 

 The diseased leg is dragged on the ground, carried outward and 

 backward and the animal resting it on the ground by the point of 

 the hoof only. It very much resembles the position of a limb of 

 a horse suffering with a dislocated patella. The anterior border 

 of the muscle, hooked by the trochanter, forms a longitudinal 

 projection, resembling a stretched cord, which becomes more and 

 more mai'ked when examined nearer the coxo-femoral joint. It 

 can be made more prominent by raising the opposite leg, when it 

 will be found extending obliquely downward from the joint to the 

 patella. As the trochanter is no longer coyered by the muscle, 

 this bony eminence becomes directly subcutaneous, and may be 

 readily recognized, holding posteriorly the displaced muscle, 

 which forms a kind of tvimor behind it. 



These symptoms, being rarely associated with inflammatory 

 phenomena, are not always easy to detect. There are cases where 

 the lameness, and the carrjdng of the leg outward and backward, 

 are the only aj)parent symptoms. The lameness, however, is 

 characteristic, and may be temporary or intermittent, being more 

 severe when the animal is traveling up-hill than when descending, 

 but remaining the same on both soft or hard ground ; and it 

 sometimes happens that while the animal is in the act of descend- 

 ing, the muscle will suddenly return to its place with a claj^ping 

 sound, and the lameness subside, though only to return again as 

 soon as the slightest effort is required of the animal, and his hind 

 leg is again carried backward more forcibly than usual. This 

 peculiar intermittent character is sometimes the cause of an error 

 of diagnosis w^hich confounds this affection with the dislocation 

 of the patella, but the exjDloration of the stifle will always serve 

 to establish the differential diagnosis. 



This accident is more or less serious in its consequences, and 

 is particularly detrimental to the usefulness of working animals. 

 It may sometimes, however, subside spontaneously or by simple 

 rest, and especially if the condition of the animal is improved by 

 good feeding with fat-producing fodder. Sometimes the displace- 

 ment is comphcated by a laceration of the mucous bursa with the 

 formation of a hygroma of warm, painful, oedematous swellings, 

 indicating the rupture of the aj^oneurosis or the inflammation of 

 the cellular tissue. 



