Co-presentation of unilateral femoral and bilateral sciatic nerve variants in one cadaver: A case report with clinical implications

This study is an anatomical case report of combined lumbo-pelvic peripheral nerve and muscular variants.University anatomy laboratory.One cadaveric specimen.During routine cadaveric dissection for a graduate teaching program, unilateral femoral and bilateral sciatic nerve variants were observed in relation to the iliacus and piriformis muscle, respectively. Further dissection of both the femoral nerve and accessory slip of iliacus muscle was performed to fully expose their anatomy.Piercing of the femoral nerve by an accessory iliacus muscle combined with wide variations in sciatic nerve and piriformis muscle presentations may have clinical significance.Combined femoral and sciatic nerve variants should be considered when treatment for a lumbar disc herniation is refractory to care despite positive orthopedic testing.The recurrence of leg pain from lumbar disc herniations is a common post treatment clinical finding. Certain muscular and peripheral nerve variants may represent an unrecognized etiology in these cases and may affect the outcome of specific treatments. Recognition of these variations in normal anatomy may be useful to the clinician when treating the patient with refractory leg pain. The femoral nerve, derived from the second to fourth lumbar dorsal divisions, is one of the terminal branches of the lumbar plexus [1]. Multiple studies have reported variant slips of the psoas and iliacus muscles which may split the femoral nerve causing a potential risk for nerve entrapment [2-9]. In a large study of 121 cadavers, Vazquez et al. reported variations of iliacus and psoas muscles piercing the femoral nerve, piercing of the femoral nerve by a muscular slip, or a muscular slip/sheet covering the femoral nerve as it lay on the iliacus in 19 specimens (7.9%) [3]. Several entities exist which may cause femoral neuropathy [10], however, owing to the lack of anatomic protection, entrapment of the nerve is most likely to occur immediately distal to the inguinal ligame