DISEASES OF BONE AND DETECTION OF LAMENESS. 93 



affected limb, are noticed, the animal's instinct leading him to place 

 the affected part in a position to relieve the pain. 



In making an examination for lameness, the animal, having free 

 use of his head, should be led at a slow trot toward and from the 

 observer. Too short a hold on the halter shank will prevent free 

 play of all the muscles concerned in locomotion. 



If lame in one fore leg, the right one for instance, the head will 

 nod (drop) more or less when he steps on the left fore leg, while the 

 head jerks up at the moment the right leg (the lame one) is placed 

 upon the ground. Hence, the head of the lame animal always nods 

 when the sound leg is planted. 



Should there be lameness in both fore Ivv;* the action is stilty (stiff) ; 

 the natural, elastic stride is wanting; the steps are shortened, and 

 the feet kept close to the ground. Almost invariably the hind legs 

 are picked up higher than normally; the shoulders appear stiff and 

 the head is carried rather high, while the lumbar region is arched. 



Lameness behind is detected by trotting the horse from the ob- 

 server, the croup being the essential part to be watched, since it 

 drops with the sound leg and rises with the lame one. 



If lame in both hind legs, the stride is shortened and awkward ; 

 the fore legs are kept back of the vertical line, and are apt to be 

 raised higher than usual, while the head is lowered. Backing is diffi- 

 cult; it is almost impossible to keep the animal at a trot when he 

 is lame in more than one leg. 



Horses lame in both fore or both liind legs show a waddling gait 

 behind, often mistaken for lameness originating in the lumbar region. 

 This peculiar motion is simply due to the fact that the hind legs are 

 unduly advanced under the body for their own relief or that of the 

 front legs. Close attention is to be paid to the animal's action as 

 he turns while being trotted to and from the observer, as at this 

 moment — that is, while he turns — any hitch becomes visible; as, for 

 instance, spavin or stringhalt lameness. 



Always place the lame leg in its natural position and inspect the 

 various parts of the leg hot 1 1 with the hand and eve, comparing them 

 always with the sound leg to find anatomical changes. 



In all cases examine the foot thoroughly and carefully, removing 

 the shoe if necessary. Heat, pain, and swelling are always guides 

 in the diagnosis of lameness. 



All lameness is divided into two classes: Swinging-leg lameness, 

 which is shown by a shortened stride and more or less dragging of 

 the leg; and supporting-leg lameness, winch shows itself when the 

 leg supports the weight of the body. The former is shown in dis- 

 eased condition of the muscles. The latter is shown in disease of 

 bone, tendons, ligaments, and the hoof. 



