Fig. 1. Schematic diagram of the flap model. The flap is pedicled on the right superior epigastric artery (A) and vein (V), which give off branches perforating the rectus abdominis muscle (M), supplying the ipsilateral part of the flap. The contralateral part of the flap is perfused indirectly via  connecting vessels to the ipsilateral part. The superficial epigastric veins (SV) are cannulated for sampling the venous blood of each part of the flap. The middle of each part of the flap (X) is where microcirculatory blood flow and tissue oxygen tension were measured. Total blood flow to the flap was measured in the right superior epigastric artery.