sacral nerve: any of five pairs of spinal nerves emerging from the sacral region of the spinal cord
spinal nerve: any of the 31 pairs of nerves emerging from each side of the spinal cord (each attached to the cord by two roots: ventral and dorsal)
hyades: (Greek mythology) 7 daughters of Atlas and half-sisters of the Pleiades; they nurtured the infant Dionysus and Zeus placed them among the stars as a reward