Categorization of voiding dysfunction on basis of 4 neurological loops that control the lower urinary tract. Loop 1, neuronal connections between cerebral cortex and pontine Ñ mesencephalic micturition center. Lesions affecting this loop (brain tumors, cerebral atrophy, stoke) cause detrusor hyperreflexia; loop 2, intraspinal connection of detrusor muscle afferent fibers to brain stem micturition center and return motor impulses. Lesions affecting this loop (spinal cord injury or transsection) cause poor emptying with residual urine; loop 3 peripheral detrusor afferent axons in spinal cord. Lesions here cause detrusor-striated sphincter dyssynergia or involuntary sphincter relaxation; loop 4A, suprasacral afferent fibers and efferent innervation of pudendal motor neurons to striated periurethral muscle and loop 4B, different segmentation of these pudendal motor neurons. Lesions here cause loss of ability to voluntarily contract detrusor.