First Method.—This is the oldest method of the three, and consists in making (1) a horizontal incision through the sensitive laminæ along the lower border of the cartilage, and (2) a vertical incision through the skin of the coronet, the coronary cushion, and a portion of the sensitive laminæ (see Fig. 139).
The flaps (Fig. 139, a, a) are now held back by tenaculæ, and the whole of the cartilage, or only the necrosed portion, carefully excised by means of right- and left-handed sage-knives. Fistulous openings in either of the flaps a, a must now be carefully curetted and dressed, and the flaps allowed to fall into position. They are then sutured with carbolized gut, and the wound finally dressed as to be described later (p. 357).
FIG. 139.—EXCISION OF THE LATERAL CARTILAGE (OLD METHOD). The wall covering the lateral cartilage first thinned and stripped off; the two flaps (a, a) of skin and the coronary cushion made by the vertical incision turned back. a, The operation flaps; b, the exposed cartilage; c, the sensitive laminæ; d, the coronary cushion.
Second Method (after Holler and Frick[A]).—These operators deem it wise to leave untouched the skin of the coronet and the coronary cushion. They therefore make their first incision along the lower border of the coronary cushion (see Fig. 140), afterwards exposing the lower half of the cartilage by removing a half-moon-shaped portion of the thinned horn and underlying sensitive laminæ (see Fig. 140, b).
[Footnote A: Two cases of quittor successfully treated by this method are reported by R. Paine, M.R.C.V.S., in the Journal of Comparative Pathology and Therapeutics, vol. xv., p. 81.]
FIG. 140.—EXCISION OF THE LATERAL CARTILAGE. (AFTER MOLLER AND FRICK.) a, The thinned horny wall covering the coronary cushion; b, the lateral cartilage exposed by stripping off the thinned wall; c, the sensitive laminæ.