Unusual innervation of the sartorius muscle by the ilioinguinal and femoral nerves with unique arrangement of the lumbar plexus: a case report and clinical implications.

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.