Nerves of Male Genital System (Left)

Description

The pudendal nerve serves as the dominant innervation of the male genital system. It gives off three main branches, namely the inferior rectal nerve, perineal nerve and the dorsal nerve of the penis. The latter two innervate the genital organs.

The perineal nerve is the inferior larger terminal branch of the pudendal nerve, which is given off inside the pudendal canal. It accompanies the perineal artery (a branch of the pudendal artery) and divides into posterior scrotal (or labial) and muscular branches. The former are double (medial and lateral) nerves which run forwards over the perineal membrane in the urogenital triangle. They provide cutaneous sensory innervation to the skin of the scrotum. The muscular branches innervate various muscles, including superficial transverse perineal, bulbospongiosus, ischiocavernosus, deep transverse perineal, sphincter urethrae, anterior parts of the external anal sphincter and levator ani muscles.

The dorsal nerve of the penis or clitoris runs anteriorly above the internal pudendal artery along the ischiopubic ramus deep to the perineal membrane.

It supplies the corpus cavernosum and accompanies the dorsal artery of the penis between the layers of the suspensory ligament. In males, the dorsal nerve of the penis runs on the dorsum of the penis to end in the glans.

There are additional nerves innervating the scrotum, such as the ilioinguinal nerve and the genital branch of the genitofemoral nerve, which innervate the anterior scrotal region via the L1 segment of the spinal cord mainly. While, the posterior scrotum is innervated by the posterior scrotal branches of the perineal nerve and the perineal branch of the posterior femoral cutaneous nerve via the L3 segment of the spina cord mainly.

Testicular nerves are derived from the T10—T11 spinal segments via the renal and aortic autonomic plexuses. Catecholaminergic nerve fibers form plexuses around smaller blood vessels and among the interstitial cells in the testis and epididymis.

Lastly, the vasa deferentia, seminal vesicles, and bulbourethral glands are innervated sympathetic nerve fibers derived from the pelvic plexus.