What is the root value of the posterior cutaneous nerve of the thigh

Posterior cutaneous nerve of thigh:- Root value:S1,S2,S3 Branch of sacral plexus. It enters gluteal region through greater sciatic foramen, below the pyriformis, and runs downwards medial or posterior to the sciatic nerve. It continues in the back of the thigh immediately deep to deep fascia. The nerve gives:1. A perineal branch which crosses the ischial tuberosity enters the urogenital triangle of the perineum and supplies skin of the posterior two -thirds of the scrotum.2. Gluteal branches which wind upwards round the lower border of the gluteus maximus, and supplies skin of posteroinferior quadrant of gluteal region. {Reference: BDC 6E pg no.72}