Variation of pectineus muscle forming a hiatus

Knowledge of the anatomic variations in the pectineus muscle is important for vascular surgeons to minimize complications following surgical approach to the distal part of the deep femoral artery. During routine dissection of the thigh, variations in the bilateral pectineus muscles were identified in an 82-year-old male cadaver. On both sides, the superficial and deep layers of the pectineus were divided at its distal part, forming a triangular-shaped hiatus between them and the femur shaft. Distally, the tendon of the superficial part intermingled with the tendon of the adductor longus. The tendon of the deep part was inserted into the pectineal line. On the right side, the deep femoral artery and its first perforating artery passed through the hiatus. On the left side, the deep femoral artery pierced the hiatus, and then, the first perforating artery was branched from the deep femoral artery. No reported case has described a pectineal hiatus. The variations observed in this study are an ontogenetic vestige of the two different origins of the pectineus. The insertion of the superficial layer into the adductor longus tendon suggests a close relationship between these muscles during prenatal development. Surgeons should be aware of the variation to minimize injury to the pectineus muscle while approaching the deep femoral artery.