Nerve Supply of the Perineal Region

• Passes through the greater sciatic foramen between the piriformis and coccygeus muscles.
• Crosses the ischial spine and enters the perineum with the internal pudendal artery through the lesser sciatic foramen.
• Enters the pudendal canal , gives rise to the inferior rectal nerve and the perineal nerve, and terminates as the dorsal nerve of the penis (or clitoris).

1. Inferior rectal nerve

• Arises within the pudendal canal, divides into several branches, crosses the ischiorectal fossa, and innervates the sphincter ani externus and the skin around the anus.
• Communicates in the ischiorectal fossa with perineal branch of the posterior femoral cutaneous nerve, which supplies the scrotum or labium majus.

2. Perineal nerve

• Arises within the pudendal canal and divides into a deep branch , which supplies all of the perineal muscles, and a superficial (posterior scrotal or labial) branch , which supplies the scrotum or labia majora.

3. Dorsal nerve of the penis (or clitoris)

• Pierces the perineal membrane, runs between the two layers of the suspensory ligament of the penis or clitoris, and runs deep to the deep fascia on the dorsum of the penis or clitoris to innervate the skin, prepuce, and glans.