The factors which determine the viability of a triangular skin flap

Experiments were undertaken on pigs to compare the survival of triangular flaps with rectangular flaps and to study the effect of the size of the apical angle on the survival of triangular flaps. Triangular random flaps survived to the same length as rectangular flaps of the same size of base, and its appears that length to breadth ratio is an important factor in determining the survival of a rectangular flap. Flaps with an apical of 60 degrees undergo necrosis if their length exceeds the safe surviving length for the size of the base of the flap, whereas flaps with an apical angle of 30 degrees survive if their length is within the surviving length for flaps of that size of base. The main effect of the apical angle may thus be to determine the length to breadth ratio.