Hoof with coronary quarter-crack, shod with a bar-shoe. The part of the quarter relieved of pressure _a_, is indicated by the dotted lines; _b_, iron plate secured by small wood screws ⁴/₁₆-⁵/₁₆ of an inch in length.] [Illustration: FIG. 221. Hoof with complete quarter-crack, shod with a bar-shoe: _a_, area thinned almost to the pododerm; _b_, ¹/₁₆ inch metal plate secured by screw ⁵/₁₆ of an inch long; _c_, quarter relieved of pressure from bottom of crack to a perpendicular dropped from top of crack.] =Quarter-crack= is usually associated with contraction of the heels. It occurs on the inner quarter of base-wide (toe-wide) hoofs, and rarely in the outer quarter of base-narrow hoofs. For quarter-cracks we use a bar-shoe and determine the extent of the wall to be laid free in the following manner: We imagine the crack to be prolonged in the direction of the horn-tubes to the plantar border, and drop a perpendicular line from the upper end of the crack to the plantar border. That part of the plantar border lying between these two points is then to be lowered sufficiently to prevent pressure from the shoe until the next shoeing (Figs. 220, _a_, and 221, _c_). This method should be followed even when the perpendicular line falls behind the buttress. The crack may be immobilized by the metal plate, or by narrow ticking bandage or adhesive tape wound a half dozen times around the hoof, in conjunction with a bar-shoe, Chadwick spring, leather sole and tar and oakum sole-packing. In dressing the hoof, the side containing the crack should be spared, the opposite side lowered, the object being to shift the weight and consequent expansion into the sound quarter. When the affected quarter is deficient in length the branch of the shoe beneath should be made thicker, even to the extent of causing it to ground in advance of the opposite branch. Next to shoeing, rubber hoof-pads render good service, because through them a part of the body-weight is distributed over the sole and frog. They assist in widening the hoof, and lessen shock when the foot is set to the ground. These are all matters which favor the growing down of unbroken horn. When the crack gaps widely, and the frog is small and deep in the foot _a shoe with bar-clips_ (Defay’s shoe), or a Chadwick spring, with bar-shoe and leather sole may be used. It is not impossible, indeed, to obtain a cure by using an ordinary open flat shoe, though much will depend upon the other lesions that may be present, the nature of the hoof, and the service required of the animal. If the edges of the crack are irregular and overlapping, they should be carefully thinned away. Thinning the horn on both sides of the crack over the coronary band, preventing drying out of the horn, and frequent applications of carbolized oil to the coronet favor growth of undivided horn and guard against a renewal of the crack.