Unusual Course of the ALT Perforator through the Rectus Femoris Muscle: Troubleshooting a Rare Variation

Abstract In 1984, Song described the anterolateral (ALT) and anteromedial (AMT) thigh flaps, both originating from the lateral circumflex femoral artery (LCFA). The conventional ALT perforator follows either a septocutaneous course—between the rectus femoris (RF) and vastus lateralis (VL)—or a musculocutaneous path through the VL, lying lateral to the RF. In contrast, AMT perforators course between the RF and sartorius or through the medial border of the RF, lying medial to it. Thus, the RF has long been considered an anatomical transition zone across which ALT and AMT perforators do not cross. This anatomical understanding forms the basis for a noncommittal incision designed to access perforators on either side of the RF. A retrospective series of 17 cases was reviewed from January 2019 to January 2025 with a dominant musculo-cutaneous perforator coursing through the RF from medial to lateral, supplying the ALT angiosome. Out of 2,856 cases, this anomaly was identified in 17 cases. All perforators originated from the RF muscle branch. Flap was harvested on this dominant perforator in 3, accidentally injured in 5, and intentionally avoided in 9 cases. The tensor fascia lata flap was the most commonly used alternate flap. In this case series, we present a rare anomaly where the only dominant perforator in the ALT zone courses through the RF muscle to join the RF muscle branch of LCFA. The nomenclature of this perforator remains contentious, as its source vessel and fascia entry point belong to different angiosomes. We also discuss strategies for managing potential complications if the perforator is inadvertently damaged.