[Illustration: FIG. 49. BITRIANGULAR EXCISION.] [Illustration: FIG. 50. LINEAR COAPTATION.] Likewise can a triangular fault be brought together by sewing in the greater angles and making a linear wound of the remaining part, as in Figs. 51 and 52. [Illustration: FIG. 51. TRIANGULAR EXCISION.] [Illustration: FIG. 52. COAPTATION OF WOUND.] Again, a triangular defect may be remedied by adding a smaller triangle at each end involving healthy skin, utilizing, if need be, the relieving incisions, as in Figs. 53 and 54. [Illustration: FIG. 53. TRIANGULAR EXCISION WITH RELIEVING INCISION.] [Illustration: FIG. 54. COAPTATION OF WOUND.] II. SLIDING METHOD Following the principle of Celsus, as mentioned on page 8, defects can be overcome in various ways. The incisions may be straight or curved, and one or more flaps of skin are raised, slid, and sutured over the part to be covered. The simplest form is the covering of a square, as shown in Figs. 55 and 56. [Illustration: FIG. 55. SQUARE EXCISION.] [Illustration: FIG. 56. COAPTATION OF WOUND.] If the square be too large for the above method, the incisions can be carried to the other side and above or below the defect, as shown in Figs. 57 and 58. [Illustration: FIG. 57. SQUARE EXCISION.] [Illustration: FIG. 58. COAPTATION OF FLAPS.] For triangular areas the curved incisions can be made, as in Fig. 59, rotating the flap into place, as shown in Fig. 60. [Illustration: FIG. 59. TRIANGULAR EXCISION.] [Illustration: FIG. 60. COAPTATION OF FLAP.] Or bilateral flaps may be utilized by straight incisions, stretched and sewn, as in Figs. 61 and 62. [Illustration: FIG. 61. TRIANGULAR EXCISION.] [Illustration: FIG. 62. COAPTATION OF FLAPS.] Again, two curved incisions are made to obtain rotating flaps, Fig. 63, and sewn, as shown in Fig. 64. [Illustration: FIG. 63. TRIANGULAR EXCISION.] [Illustration: FIG. 64. ARRANGEMENT OF FLAPS.] Bürow introduced a method for closing over defects by sliding flaps in which he utilized the mobility of skin obtained by the excision of triangles of healthy skin. The results are exceedingly good, but, unfortunately, the sacrifice of skin affects its general use, inasmuch as patients can afford but little loss of healthy skin; besides, there is the objection of added scarring. The closing of a triangular defect by this method is shown in Figs. 65 and 66, in which _a_ is the triangular defect and _b_ the triangle of healthy skin excised. The skin about the incisions is dissected up and the flaps are sutured into position, as shown in Fig. 66. [Illustration: FIG. 65. DOUBLE TRIANGULAR EXCISION.] [Illustration: FIG. 66. COAPTATION OF WOUND.] Where the triangular defect has a wide base, bilateral triangular sections of skin are removed (Fig. 67), and the flaps are coapted, as in Fig. 68. [Illustration: FIG. 67. TRI-TRIANGULAR EXCISION.] [Illustration: FIG. 68. COAPTATION OF WOUND.]