A-C, Principles of three types of local flaps. In each type, defect to be covered is converted into triangular one. Flap may be rotated (A) or transposed (C) or both (B). B, Back-cut in combined flap decreases tension on flap but also decreases blood supply to flap; defect created by this back-cut is closed as shown. C, Defect created by transposing flap must be covered with split-thickness graft.