With the increasing popularity of perforator flaps as "musculocutaneous flaps without muscle," a new interest in the intercostal vessels as source vessels for perforator flaps has arisen. In a recent study, the branches of the three lowermost intercostal vessels to the latissimus dorsi were studied in detail. Now that these muscular branches are well understood, the present study examines how many of these branches reach the overlying skin as musculocutaneous perforators. We identified the intercostal artery perforators in the ninth, tenth, and eleventh interspaces, in 42 hemithoraces. Only branches that measured 0.5 mm or more in external diameter were included. The course of the perforators was followed from their exit from the latissimus dorsi muscle up to the entrance at the undersurface of the skin. This entrance point was punctured by a pin and thus marked on the skin. This study showed that at least three musculocutaneous perforators were present over the intercostal spaces IX-XI in every dorsal hemithorax (average 8 +/- 3, range 3-16). Potentially, each of these vessels can be used as a pedicle for a separate perforator flap, leaving the more proximal parts of the latissimus dorsi intact for a second flap based on the dominant thoracodorsal vessels.