Perineal nerve

Last revised by Henry Knipe on 29 Jan 2024

The perineal nerve, also known as the perineal branch of the pudendal nerve, is the largest terminal branch of the pudendal nerve which is derived from S2, S3 and S4 nerve roots of the sacral plexus. The perineal nerve gives muscular branches to the superficial and deep perineal muscles as well as the external urethral sphincter.

The perineal nerve is the largest and most inferior of the three branches of the pudendal nerve (the other branches being the inferior rectal nerve and the dorsal nerve of the penis or clitoris). The nerve originates in the pudendal canal, which is formed by the fascia of the obturator internus muscle.  

After passing into the perineum, the pudendal nerve bifurcates into two terminal branches: the perineal nerve which travels superficial to the urogenital diaphragm, and the dorsal nerve which passes deep to it.

After bifurcating from the dorsal nerve, the perineal nerve passes into the urogenital triangle superficial to the urogenital diaphragm. The nerve then travels anteriorly over the superficial transverse perineal muscles and ramifies into terminal cutaneous and motor branches.

As the perineal nerve travels anteriorly on the superficial surface of the urogenital diaphragm, it branches into superficial and deep branches.

The perineal branch of the pudendal nerve is closely associated with the internal pudendal artery and its branches. Within the pudendal canal the terminal branches of the pudendal nerve run with the internal pudendal artery. The dorsal nerve runs superior to the internal pudendal artery and the perineal nerve travels inferior to it. After exiting the pudendal canal, the posterior scrotal or labial branch of the internal pudendal artery is closely related to the superficial branch of the perineal nerve, and the muscular branches of the perineal nerve are related to the superficial and transverse perineal arteries.  

Regional anesthetic blocks targeting the pudendal and perineal nerves have been used in vaginal deliveries and for minor surgeries of the vagina and perineum, as well as in chronic perineal pain ref.

ADVERTISEMENT: Supporters see fewer/no ads

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.