Sensory and somatomotor components of the "sensory branch" of the pudendal nerve in the male rat.

Surgical microscopy and electrophysiological techniques were used to describe in the adult male rat the peripheral distribution of the sensory branch of the pudendal nerve (SBPdn) and its sensory and somatomotor axonal components. Gross and histological features of the urethralis muscle were also determined. We propose to name the SBPdn branches according to the corresponding target structure. We found branches to the urethral diverticulum, major pelvic ganglion, corpus cavernosus of the penis, urethralis muscle, preputial glands, corpus spongiosus of the penis, foreskin and glans penis. Under the pubic bone three anastomotic branches form a bridge-like structure we called pelvic plexus. Through electrophysiological studies it was determined that the SBPdn carries efferent fibers to the striated urethralis muscle, as well as afferent axons from the glans penis and foreskin. We concluded that the SBPdn of the male rat has sensory and somatomotor components. This nerve is mixed and not exclusively sensory as was previously described. The finding of the anatomic relation to the major pelvic ganglion implies nerve communication with the autonomic nervous system. The functions of the somatomotor component and nerves to the urethral diverticulum, cavernosus bodies and preputial glands of the SBPdn remain to be determined. According to its targets, this innervation could contribute in the control of genitourinary functions such as voiding, erection, ejaculation and urinary marking.