132 THE SURGICAL ANATOMY OF THE HORSE 



THE TENDON OF THE MIDDLE GLUTEUS MUSCLE 

 AND ITS BURSA— FALSE HIP LAMENESS 



It will be remembered that one of the tendons of insertion of the 

 great or middle gluteus muscle plays over the outer surface of the 

 convexity of the great femoral trochanter and obtains insertion into 

 the crest. This is a very powerful tendon, and as it passes over the 

 convexity it becomes very much flattened out. The outer surface of 

 the convexity is covered by a layer of smooth fibro-cartilage, and 

 still further to facilitate the gliding movements of the tendon, there 

 is interposed between it and the convexity an ovoid synovial sac or 

 bursa. This bursa is disposed with its long axis directed downwards 

 and forwards. Inflammation of this tendon and its bursa constitutes 

 what is known as False Hip Lameness, to which attention was first 

 directed by Gunther and which Williams described under the name 

 of trochanteric lameness. Williams states that " lameness in the hip 

 is not at all an infrequent occurrence ; still its seat is not the joint 

 but the head of the trochanter major of the femur." MoUer states 

 that the disease is only occasionally seen in horses ; the fact remains 

 that the great trochanter, with the structures playing over it, are 

 particularly exposed to risk of injury and form a prominent land- 

 mark in the living animal, especially in subjects of low muscular 

 development in which less protection is afforded. The tendon may 

 be sprained and the bursa injured by violent exertion on the part 

 of the muscle. But the injury is most frequently the result of a blow 

 or a fall when this part comes into contact with the hard road or 

 pavement as the animal comes down on its broadside. Lameness 

 occurs, regarding which Williams states " there is a hop and a catch 

 in the lame limb and a want of movement in the quarter which, 

 to a practised eye, is quite suggestive. The whole of the quarter on 

 the lame side is elevated with as little motion of the hip as possible. 



