Journal of the Medical Association of Thailand Vol 91, No 8:AUGUST 2008 0125-2208 91 8 2008 Aug Anatomical Study of the Superior Gluteal Artery Perforator (S-GAP) for Free Flap Harvesting 1244 EN Tanvaa Tansatit Prayuth Chokrungyaranont Pasinee Sanguansit Samang Wanidchaphloi Original Article To present the appropriate superior gluteal branch for free flap harvesting. The characteristic and external diameter of the pedicles and the main perforators, andlength of the pedicles were studied in both sides of 30 formalin-preserved cadavers. The patterns of the pedicle could be classified into four types, the vertical, the horizontal, the descending,and the penetrating main branches. The descending branch was the longest (7.33 + 1.3 cm). While the pedicleand perforator of the horizontal branches was the largest (2.7 + 0.6 mm and 1.2 + 0.2 mm, respectively).However, it was difficult to dissect the vertical and the horizontal branches because the vessel courses didnot run in the direction of the muscle fiber. Whereas the penetrating main branches were observed in theintermuscular septum so, it was easy to approach the pedicle. The length (5.3 + 1.3 cm) and external diameter(2.17 + 0.5 mm) of the pedicle were adequate for free flap harvesting. In the anatomical study, the penetrating pedicle was recommended to use for the S-GAP flap. Superior gluteal artery Perforator flap