Evoked response of the bulbocavernosus reflex.

The bulbocavernosus reflex can be elicited either by penile or urethral stimulation. The mean signal transit time after electrostimulation of the dorsal penile nerve to evoked response in the anal sphincter (35 msec) was only half the signal transit time after stimulation in the posterior urethra (60 msec). Thus, the modified bulbocavernosus reflex elicited either by squeezing the glans penis or by pulling a urethral balloon catheter represents two different reflexes with differenct afferent and probably different intraspinal pathways. In the clinic it is therefore important, when testing the bulbocavernosus reflex, to report how it is elicited.