Function: The nerves to the pelvis intermingle the sensory, somatic, sympathetic,  and parasympathetic components. The sensory cutaneous nerves are described in the integument. Other sensory nerves, eg. urethra, vagina, anal canal,  detect touch, temperature, and pressure stimuli in those organs. The somatic nerves supply motor stimuli to skeletal m., maintaining their 'tone', and allowing voluntary relaxation. The sympathetic n. regulate blood flow in the region, and smooth muscular contractions, particularly noted in constriction of the bladder neck, and in contractions of the uterus. The parasympathetic n. have a vasoregulatory action on erectile tissues, and important roles in detection of bladder and rectal fullness and emptying.  The uterus has little parasympathetic innervation, possibly accounting for its capacity for progressive distension during pregnancy without inappropriate contractions.