Sidebones.

Sidebones.

On each side of the bone of the hoof the coffinbone there are normally two supplementary organs which are called the cartilages of the foot. They are soft, and though in a degree elastic, yet somewhat resisting, and are implanted on the lateral wings of the coffinbone. Evidently their office is to assist in the elastic expansion and contraction of the posterior part of the hoof, and their healthy and normal action doubtless contributes in an important degree to the perfect performance of the functions of that part of the leg. These organs are, however, liable to undergo a process of disease which results in an entire change in their properties, if not in their shape, by which they acquire a character of hardness resulting from the deposit of earthy substance in the intimate structure of the cartilage, and it is this change, when its consummation has been effected, that brings to our cognizance the diseased growth which has received the designation of sidebones. They are situated on one or both sides of the leg, bulging above the superior border of the hoof in the form of two hard bodies composed of ossified cartilage, irregularly square in shape and unyielding under the pressure of the fingers.