2. Curative.

(a) The Application of Dressings to the Lesion. - In the case of a recent crack, deep, and attended with haemorrhage, the foot should be thoroughly cleansed. Where possible, a constant flow of cold water from a hose-pipe should be allowed to run over the foot. By this means the inflammatory symptoms will be held in check and pain prevented. Later the shoe may be eased at the required place, and a blister applied to the coronet. This, with rest, will sometimes prove all that is needed.

Should a crack be of old standing, and complicated by the presence of pus, a course of hot poulticing will often prove of benefit. The poultice should be medicated with any reliable disinfectant, and should be renewed, or at any rate reheated, two or three times daily. The crack itself should be thoroughly cleaned after the removal of each poultice, and a concentrated antiseptic solution - such as Tuson's spts. hydrarg. perchlor., carbolic acid, and water, (1 in 10) or liquor zinci chlor. - poured into it. On discontinuing the poulticing, the strength of the antiseptic solutions may be decreased, the parts rested by correct shoeing, and a blister applied to the coronet as before.

If these measures alone should prove insufficient, then the surgeon will either fall back on those we have just related, or proceed to methods next to be described.

(b) Immobilizing the Crack by Means of grooving the Wall. - To our minds, this is as ready and withal as successful a method of dealing with sand-crack as has yet been devised. It may be done in a variety of ways: (1) By two grooves arranged about the crack in the form of a V, as Fig. 94; (2) by a perpendicular groove on either side of the crack, about 1 inch in distance from it, and parallel with the horn fibres, as Fig. 95; (3) by a single horizontal groove at the extreme upper limit of the crack; (4) by drawing two horizontal grooves, one at its upper and one at its lower end (see Fig. 96).

Diseases Arising From Faulty Conformation A Sand C 094Diseases Arising From Faulty Conformation A Sand C 095Diseases Arising From Faulty Conformation A Sand C 096

FIG. 94

FIG. 95

FIG. 96

In Figs. 94, 95, and 96 the thick black lines illustrate the positions of the various grooves made with the firing-iron for the purpose of immobilizing a quarter sand-crack.

The points to be observed in carrying out this line of treatment are simple enough. In all cases see that the crack is rendered as clean as possible by the use of suitable dressings, and if an excess of horn is present immediately around it, as in the case of a long-standing and complicated lesion, have it thinned down by rasping.

All that is then needed is one or two moderately sharp, flat firing-irons. The groove is then burned into the horn in the positions indicated, and that portion of the wall containing the sand-crack thus prevented from participating in the movements of the foot. For our own part, we consider the V-shaped incision, or either of the horizontal methods of grooving, preferable to lines running in the direction of the horn fibres. With the latter there is certainly a greater tendency to the formation of new cracks than with either of those we advocate. The V-shaped incision we consider most suitable of all, for the reason that by its means a greater degree of immobility is conferred upon the necessary portion of the wall.

Whichever method is adopted, care should be taken to carry the grooves deep enough into the horn, taking them down as near as possible to the sensitive structures. At the same time, especial care should be exercised in not carrying them too deep at their extreme upper limit, or in that case the liability to the formation of fresh cracks in those positions will be greatly increased. vAfter grooving, a sharp blister should be applied to the coronet every three or four weeks, and the animal, if free from lameness, put to work.

(c) By stripping away a V-shaped Portion of the Wall around the Crack. - This method is only indicated when the crack is greatly complicated by the presence of pus, or by the growth of adventitious horn on the inner surface of the wall. A radical cure is thus obtained, but the animal for a longer time incapacitated from work.

The operation is best performed by first grooving a line to connect the points a and c (Fig. 97). This should run immediately under the coronary margin of the wall, and should stop short of injuring the coronary cushion beneath. Grooves forming the sides ab and bc of the triangular piece of horn are next made, and the horn contained within the lines ab, bc, and ca, carefully removed. The grooves are the easiest made by a cautious use of the firing-iron. The greater thickness of the horn may thus be penetrated, and the grooves afterwards carried to their full and requisite depth by the use of the drawing-knife.

With the removal of the horn the diseased structures are exposed to view. All such should be removed by a free use of the scalpel, and a suitable dressing afterwards applied. A necessary factor in the treatment is the employment of pledgets of antiseptic tow. With these the exposed tissues are covered, and the successive turns of a bandage run tightly over them, so as to exert a moderate degree of pressure. When haemorrhage has accompanied the operation, this dressing should be removed on the following day, the wound dressed, and the pledgets of tow and the bandage renewed. Any after-dressing need only then be practised at intervals of a week. Repair after this operation is rapid, and takes place both from the exposed podophyllus membrane and from the coronary cushion.

Fig. 97. The Dotted Lines Outline The V Shaped Portion Of Wall To Be Removed In The Treatment Of Complicated Toe Crack

Fig. 97. The Dotted Lines Outline The V-Shaped Portion Of Wall To Be Removed In The Treatment Of Complicated Toe-Crack.

Fig. 98. The dotted lines indicate the portion of wall to be removed in the complete operation for complicated toe crack

Fig. 98. The dotted lines indicate the portion of wall to be removed in the complete operation for complicated toe-crack.

(d) By stripping the Wall from the Coronary Margin to its wearing Edge on Either Side of the Crack. - This is merely a more extensive application of the method just described, and is only indicated in a complete and complicated crack that has refused to yield to other modes of treatment (see Fig. 98).

As in the previous case, a groove is run from a to c. The grooves ab and de are then continued to the lowermost edge of the wall, and the whole of the wall within these points removed. To facilitate removal, the white line should be grooved between the points b and d. After-treatment is exactly the same as that just referred to.