Principles and descriptions of design of skin flaps for use on the lower extremity

Distinction must be made between tissue movability and tissue elasticity when considering tissue movement with the hope of predicting good results. Tissue movability is either inherent, as on the back of the thigh, or is created by undermining, back-cutting, or cutting out Bürow's triangles. The elasticity of skin is inherent everywhere and is difficult to accurately predict. Elastic tissue will gape when cut, whereas inelastic tissue will not. Finally, elastic tissue will rotate with little puckering but inelastic tissue will form large dog-ears when rotated. For these reasons, as soon as the decision has been made to use a flap it is important to "prethink" the dynamics of flap movement and decide which type of flap to use and what is to be accomplished. If consideration is given to which flap will best allow proper transfer of tissue and at the same time give the best cosmetic result, the task is usually simpler. By further considering the secondary movement of surrounding tissues (as well as the primary movement), the number of potential techniques and designs are greatly increased.