Variations in origin and relation of the posterior cutaneous nerve of the thigh with piriformis muscle

Background: The gluteal region includes a disproportionate number of nerves of all sizes, both motor and sensory. The piriformis is the uppermost of the small muscles of the gluteal region and the key to the arrangement of nerves and vessels in the buttock. The posterior cutaneous nerve of the thigh usually supplies the posterior aspect of the thigh and, according to literature the nerve terminates at the popliteal region or proximal leg. The study was undertaken to record the variations in emergence of the posterior cutaneous nerve of the thigh and its relation to piriformis muscle. Methods: Comprised of 60-lower extremities with gluteal region from 30 embalmed adult human cadavers (52 male and 8 female specimens). Any variation in the emergence of the posterior cutaneous nerve of the thigh in relation to piriformis was noted. Results: In the present study piriformis consisted of one belly in 55 specimens (91.67%) and two bellies of piriformis were observed in 5 specimens. In present study the posterior cutaneous nerve of thigh was emerging below the piriformis in 56 specimens (93.33%) and in 4 specimens (6.67%), the relation of posterior cutaneous nerve of thigh with piriformis was found variable which were grouped as type A, type B and type C. Conclusions: Knowledge of variant relation of posterior cutaneous nerve of thigh with the piriformis is important as entrapment of this nerve may lead to pain in the area innervated by posterior cutaneous nerve of thigh.