Fig. 81.—Deformity resulting from Laminitis.
Fig. 81.—Section showing how front of wall is separated from sensitive laminæ.
Sandcracks. This is the name given to cracks in the wall which commence at the coronet and extend downwards. From their position at the toe, or at the side of the hoof, they are sometimes called respectively "toe-cracks" and "quarter-cracks." The crack may be very slight and may exist without causing lameness. It may appear suddenly, accompanied by great lameness and by the issue of blood from between the edges of the divided wall. These are grave cases which require surgical attendance. Sandcracks are most commonly seen in dry brittle feet, and the horses most subject to them are those employed in heavy draught work. Railway shunt-horses and omnibus horses are very liable to be troubled with sandcracks in the toe of the hind feet.
In shoeing for this defect there are two things to avoid, (a) not to place any direct pressure on the part; (b) not to fit a shoe which will tend to force the crack open. Following these lines it is well not to put a clip exactly over a crack. If at the toe place a clip each side of the crack, and never use calkins or high heels which throw the weight forward. If at the quarter avoid a spring-heeled shoe which permits the downward movement of the foot behind the crack and so forces it open. In all cases, after fitting the shoe level to the foot, remove a little more horn just below the crack so as to relieve the direct bearing on the part. ([Fig. 82]).
Fig. 82.
A—Horn removed to prevent pressure.
Bearing relieved at wrong place by "springing" the heel.