sacral spinal nerve 1 sacral spinal nerve 1 the sacral spinal nerve 1 (s1) is a spinal nerve of the sacral segment.sacral spinal nervethe plan of the lumbosacral plexusdetailsidentifierslatinnervi spinalisfma6423anatomical terminology it originates from the spinal column from below the 1st body of the sacrum sacrum, showing bodies in center. muscles s1 supplies many muscles, either directly or through nerves originating from s1. they are not innervated with s1 as single origin, but partly by s1 and partly by other spinal nerves. the muscles are: gluteus maximus muscle gluteus medius muscle gluteus minimus muscle tensor fasciae latae piriformis obturator internus muscle inferior gemellus superior gemellus quadratus femoris semitendinosus gastrocnemius flexor hallucis longus abductor digiti minimi quadratus plantae additional images sacral spinal nerve 1 sacral spinal nerve 1 sacral spinal nerve 1