Urinary striated sphincter: what is its nerve supply?

Innervation of the voluntary urinary sphincter continues to be a controversial subject. Using retrograde axonal transport techniques to determine the exact nerve supply to the external sphincter has been successful in clarifying this controversy. 1-5 Tracing the transport of horseradish peroxidase (HRP) injected in the voluntary external sphincter and that injected directly in the cut end of the pudendal nerve was done. Transport from both sides ended in the same neurons in the dorsolateral column, thus labelling and identifying the pudendal nucleus which is the motor center for the voluntary urinary sphincter.