Background: Free flap is one of modality to close the defects in plastic surgery. To close the defects in hand, foot, head and neck, the flap that needed is the thin and pliable flap to reach the good quality and aesthetic result. One of the effort to obtain thin and pliable flap is by preserving the perforator vessel and removing the fat tissue, both procedure can be done during the elevation of the flap. In this study we try to show the pattern of subdermal plexus, perforator vessels and subcutaneous fat on anterolateral thigh, deep inferior epigastric artery perforator and thoracodorsal artery perforator flap. This pattern can be used to make the thinning procedure easier.Patient and methods: The study is performed on five fresh cadaver. After elevating the 9X15 cm flaps, we inject the vessel with colored latex solution. According to the pattern of colored vascular plexus then we perform the thinning procedure. Flap thickness and position of subdermal plexus are measured, also the form of fat lobule is observed.Result: We elevate 23 flaps, the thicker is DIEAP (mean 11,7 mm), ALT (mean 14,5 mm) and TAP (mean 9,0 mm). The subdermal plexus site from the skin is 2,3 mm on ALT flap, and 2,0 mm on DIEAP and TAP flap. The form of fat lobule according to the superficial fascia is lamellar on deep layer and areolar on superficial layer, the subdermal plexus is sitting superficial to the areolar form of fat lobule. Conclusion: The safe thinning procedure according to our study can be performed to the deeper layer of subdermal plexus (2,0-2,3 mm from the skin), or within the areolar form of fat layer.