A unique case of bilateral sciatic nerve variation within the gluteal compartment (915.9)

Abstract

In the course of routine cadaver dissection, variants in the emergence of the sciatic nerve (SN) from the pelvis to the gluteal compartment were discovered bilaterally. Meticulous dissection was used to isolate and visualize the SN via lateral reflection of the gluteus maximus showing the SN and its variants described herein. In the left gluteal region, the SN had a high division where the fibular division exited the pelvis superior to the piriformis muscle while the tibial division exited inferior to the piriformis. Additionally, in the right gluteal region, the fibular division was observed to have split the piriformis muscle before it joined the tibial division of the SN which exited the pelvis inferior to the piriformis muscle. An abnormal pathway of a nerve’s course emerging through or around a muscle may yield dual or anomalous innervation of a muscle. As it applies to this case, speculation may be placed on the patient’s piriformis and gluteus maximus muscles receiving variant innervation by the SN or a division of that nerve. Further, if inappropriately trapped within the confines of a muscle or regular boundaries, variant emergence of a nerve could give rise to distal neuropathy. As was seen in this case the patients right piriformis muscle, having been split by the SN, appears atrophied in comparison to the patients left piriformis muscle, which was entrapped by fibular and tibial divisions of the SN.