The present review describes the neuronal innervation of the external ureth
ral and anal sphincters, A knowledge of this innervation helps in understan
ding the clinical symptoms of urinary and anorectal pathology, and in choos
ing the appropriate technique of nerve localization or block. An ability to
locate the pudendal nerve, on the basis of surgically documented anatomy,
has important diagnostic and therapeutic advantages. It can be used to stud
y the integrity of pelvic floor muscles, in biofeedback training, nerve blo
cks, pudendal canal decompression, chronic stimulation trials to treat urin
ary or faecal incontinence, and in nerve conduction studies or evoked poten
tial recordings. Furthermore, the superficial location of the sphincteric i
nnervation in the perineum and ischiorectal fossa renders the nerve branche
s susceptible to injury during operative correction of urinary or faecal in
continence. Supported by a knowledge of anatomy, we can make firm recommend
ations on which to base safe surgical techniques that avoid damage to ureth
ral and anal sphincteric innervation. (C) 2000 Lippincott Williams & Wilkin
s.