Innervation of the anterior perineal muscles and its morphological consideration.

3 male and 3 female pelvic-halves were dissected carefully under a stereomicroscope in order to obtain more detailed data on the nerve supply to the anterior perineal muscles. At its origin from the pudendal plexus, the perineal nerve has a close relationship with the dorsal nerve of the penis or clitoris, while it tends to be separate from the inferior rectal nerve. The ischiocavernosus and the transversus perinei profundus are in general supplied by a common branch which arises from the perineal nerve at the posterior part of the ischiorectal fossa and takes a more lateral course, independent of the cutaneous branches. The bulbospongiosus and the transversus perinei superficialis receive several twigs from the medial and intermediate cutaneous branches of the perineal nerve. From the view point of nerve supply, the anterior perineal muscles may be classified into 2 groups: the lateral group comprising the ischiocavernosus and the transversus perinei profundus, the medial group comprising the bulbospongiosus and the transversus perinei superficialis.