Variations in the course and branching pattern of sciatic nerve in the gluteal region with surgical implications

Sciatic nerve is vulnerable to iatrogenic injuries during intramuscular injections in the gluteal region because of its course and relations in the gluteal region. It originates from sacral plexus, usually in the pelvic cavity and enters the gluteal region through the greater sciatic foramen below the piriformis. The level of its termination by dividing into tibial and common peroneal nerves varies. The present study is undertaken to measure the width and thickness of sciatic nerve in the gluteal region as well as to measure the length of sciatic nerve till its terminal division in 46 lower limbs. Among the 46 lower limbs studied the SN was below the piriformis in 40 specimens (87%), between the fibres of piriformis in 2 specimens (4%), above and below the superior gamellus in 3 limbs (7%) and it divided before entering the gluteal region in 1 (2%) lower limb. Since lower limb surgeries frequently involve sciatic nerve block, time to time documentation of usual and unusual course of sciatic nerve in the gluteal region becomes worthwhile.