The sartorius muscle is typically innervated by two branches of the femoral nerve arising from the lumbar plexus. We present an unreported variant where the sartorius muscle was innervated by an accessory branch arising from the ilioinguinal nerve in addition to the proper two branches from the femoral nerve. The iliohypogastric nerve was fused with the ilioinguinal nerve. More proximally, the lumbar plexus also showed unusual arrangement. The anterior branch of the lateral femoral cutaneous nerve arose from the femoral branch of the genitofemoral nerve while the posterior branch arose directly from the second lumbar nerve. The genital branch of the genitofemoral nerve pierced the psoas major muscle more distally than usual, and featured a close proximity with the femoral nerve. Possible variable appearance of these nerves should be kept in mind during several surgical and diagnostic procedures since their iatrogenic or traumatic damage, or their susceptibility to entrapment, pose unpredictable clinical consequences.

Center for Endoscopic Surgical and Clinical Anatomy 2nd Faculty of Medicine Charles University Prague Czech Republic

Department of Anatomy 2nd Faculty of Medicine Charles University 5 Uvalu 84 Prague 5 Prague 150 06 Czech Republic

Department of Health Studies College of Polytechnics Jihlava Jihlava Czech Republic

Department of Orthopaedics 1st Faculty of Medicine Charles University and Motol University Hospital Prague Czech Republic

Spinal Surgery Unit Oxford University Hospitals NHS Foundation Trust Oxford UK

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