The pudendal nerve is the main nerve that serves the perineum, which is the area between the anus and the genitalia (the scrotum in men and the vulva in women). It carries sensory information (sensation) from the external genitalia and the skin around the anus and perineum. Additionally, it transmits motor signals, which cause movement, to several pelvic muscles.
The pudendal nerve is the second lowest of the 31 spinal nerves. All spinal nerves are paired but generally are referred to as a single nerve and, when necessary, differentiated by the side of the body they serve.
The spine is divided into five regions. From top to bottom, these regions are:
Five nerves, including the pudendal nerve, emerge from the spinal cord in the sacral region and just one from the coccygeal region below it. The sacral region begins just below the top of your pelvic bone and ends just above your “tail bone,” or coccyx.
The sacral nerves are:
- Superior gluteal nerve (S1)
- Inferior gluteal nerve (S2)
- Sciatic nerve (S3)
- Posterior cutaneous nerve (S4)
- Pudendal nerve (S5)
The pudendal nerve divides into three main branches, which are the:
- Inferior rectal nerve
- Perineal nerve
- Dorsal nerve of the penis or clitoris
These nerves, in turn, divide into more parts as they connect to different muscles and other tissues.
After branching out from the spinal cord, the pudendal nerve’s path resembles a rough “C” shape. It passes between the coccygeus and piriformis muscles, which are deep in the buttocks and behind the gluteus maximus. It then leaves the pelvis through an opening in the bone called the greater sciatic foramen, crosses over the sacrospinous ligament, then goes back inside the pelvis via the lesser sciatic foramen.
It then runs through a sheath of fascia (connective tissue) that’s called the pudendal canal. That’s where it divides into the inferior rectal, perineal, and dorsal nerves.
The pudendal nerve has motor and sensory functions in the pelvis and plays an important part in both sexual function and continence.
Nerve signals from the brain are what moves your muscles. The pudendal nerve transmits signals to various muscles in the perineum and the pelvic floor, including:
- Levator ani
- External anal sphincter
- External urethral sphincter
The pudendal nerve provides sensation to the:
- Posterior scrotum
- Anal canal
Other nerves provide sensation to these areas, as well.
Role in Sexual Function
The pudendal nerve sends signals to the central nerves system that are involved in both penile and clitoral erection. It’s also responsible for male ejaculation.
Causes of pudendal neuropathy include:
- Trauma due to childbirth
- Gynecological or colo-rectal surgery
- Other trauma to the pelvis and/or buttocks
- Diabetic neuropathy
- Excessive sitting on a hard surface, as with cyclist’s syndrome
- Excessive physical exercise
- Thickening of ligaments in the region
- Bony formations putting pressure on the nerve
- Chronic constipation
- Poor posture
Symptoms of pudendal neuropathy are felt in the genitalia, urethra, perineum, anus, or rectum. They include:
- Pain that is burning, shooting, aching, or like an electric shock
- Itching or raw feeling
- Sexual dysfunction and/or pain during intercourse
- Difficulty sitting
- Bladder pain or dysfunction
- Bowel pain or dysfunction
- A full sensation in the rectum or vagina (rarely)
- Pain while sitting but not while standing
- Phantom pain in the buttocks, legs, and feet due to sensation there being supplied by nearby spinal nerves
Treatment depends largely on the cause of your pudendal neuropathy. It may include any combination of the following:
- Sitting on a “donut” cushion
- Nerve blocks (which may also be used as a diagnostic tool)
- Anticonvulsant or antidepressant medications
- Nerve decompression surgery