QUARTER-CRACK. A form of sandcrack, a disease of the horse; specifically a vertical crack on the lateral part of the wall of the foot. When the crack is directly in front it is called a toe crack. Toe cracks are most common in the hind feet, while quarter-cracks nearly always affect the for feet and similarly the inside quar ter is more liable to the injury than the outside one, in that when in motion it is subject to a greater part of the weight of the horse. In the normal foot the coronet o•, for authorities differ, the sensitive laminw, which cover the external surface of the pedal hone. secretes an adhesive material which binds firmly together the fibres of the wall of the hoof. When the secreting mem brane is prevented from carrying out its func tions the material secreted under such conditions loses its power. and the horn which it supplies becomes deficient in strength. Where this disease is of hereditary tendency the horn is so weak that it would seem to split, if subjected to a violent strain. Ordinarily, the various forms of sand crack are caused by the much to be condemned system of using seated shoes and of paring the frog, an unnatural custom by which the entire weight of the animal is thrown on the crust of the foot. instead of being properly distributed be
tween the wall, the frog, the outer portion of the sole, and the bars. Among other causes of per verted secretion may be mentioned the strain of fast work, and hard ground. Cracks or splits naturally occur in that part of the hoof which receives the greatest amount of strain, usually the inner quarter of the fore, and the toe of the hind foot, although it sometimes cracks at the toe of the fore foot, if the hoof is of a fiat conformation. Cart and cab horses are especially liable to sand c•ack. The usual treatment is: (1) To prevent movement between the edges of the crack; (2) to heal the exposed tissues should they be wounded or inflamed; and (3) to encourage the downward growth of sound horn from above the creek. for it is evident that as the edges of the crack cannot reunite the growing down of the crack is the only effective remedy. An authoritative and comprehensive treatment of this subject may be found in Hayes, Veterinary :Votes for horse Owners (London. 1897).