Figure 1 .

Neural and anatomical connections of normal lower urinary tract control. Afferents from the bladder and pelvic floor enter the spinal cord at the thoracic and sacral levels where they send ascending projections or synapse with local neurons. Descending modulation from the periaqueductal gray (PAG) and pontine micturition center (PMC) coordinates bladder and sphincter activity by controlling the output of the preganglionic sympathetic nucleus (PSN), sacral parasympathetic nucleus (SPN), and Onuf's nucleus. Abbreviations: cranial sensory nerve (CSN), dorsal nerve of the penis (DNP), external anal sphincter (EAS).