The pudendal nerve controls bladder and bowel continence, delivers sensation to the genitals and perineum, and powers the muscle contractions involved in sexual function. It originates from the S2 through S4 spinal nerve roots near the base of the spine and branches into three divisions that serve the entire pelvic floor region. When this nerve works properly, you rarely think about it. When it doesn’t, the effects can be life-altering.
Where the Nerve Runs
The pudendal nerve forms from three nerve roots (S2, S3, and S4) in the sacral plexus, the nerve network at the very bottom of your spinal cord. From there, it takes a winding path through the pelvis. It exits through an opening in the pelvic bone called the greater sciatic foramen, crosses between two tough ligaments (the sacrospinous and sacrotuberous ligaments), then re-enters the pelvis through the lesser sciatic foramen. It then travels through a narrow tunnel called the pudendal canal, or Alcock’s canal, running alongside the pudendal artery and vein along the side wall of the pelvic floor.
This complex route matters because each turn and tunnel is a potential compression point. The nerve passes through tight spaces between bones, ligaments, and muscles, making it vulnerable to being squeezed or stretched in ways that most nerves elsewhere in the body are not.
The Three Main Branches
The pudendal nerve splits into three branches, each with a distinct job:
- Inferior rectal nerve: Supplies motor control to the external anal sphincter, giving you voluntary control over bowel movements. It also carries sensation from the skin around the anus and the lower portion of the anal canal.
- Perineal nerve: Divides further into superficial and deep branches. The superficial branch delivers sensation to the skin of the perineum, the labia in women, or the posterior scrotum in men. The deep branch controls the external urethral sphincter, which is the muscle that lets you voluntarily start and stop urination. It also innervates muscles involved in erection and ejaculation.
- Dorsal nerve of the penis or clitoris: Carries sensation from the penis or clitoris back to the spinal cord and brain. This is the primary nerve responsible for genital sensation during sexual activity.
Bladder and Bowel Control
The pudendal nerve’s most essential everyday role is maintaining continence. Its motor fibers control the external urethral sphincter and the external anal sphincter, the two muscles that let you consciously decide when to urinate or have a bowel movement. Without functioning pudendal nerve signals, these sphincters lose voluntary control, which can lead to urinary or fecal incontinence.
The motor fibers that drive these muscles originate from a specialized cluster of nerve cells in the sacral spinal cord called Onuf’s nucleus. This cell group is unique in the body because it controls striated (voluntary) muscles that serve an autonomic-style function: keeping sphincters closed until you deliberately relax them.
Role in Sexual Function
The pudendal nerve is central to sexual response in both men and women. Sensory fibers from the genitals carry touch and pressure signals through the nerve to the spinal cord, where they trigger reflexes that contribute to arousal, erection, and lubrication. These signals also travel upward to brain areas involved in sexual pleasure and orgasm.
On the motor side, the nerve controls the bulbospongiosus and ischiocavernosus muscles. In men, these muscles help maintain penile rigidity during erection and produce the rhythmic contractions of ejaculation. In women, the same muscles support clitoral engorgement and the pelvic contractions during orgasm. Men and women share a remarkably similar pattern of genital nerve anatomy and physiology, and many of these sexual reflexes work through the same spinal pathways in both sexes.
What Pudendal Nerve Damage Feels Like
When the pudendal nerve is compressed, stretched, or injured, the resulting condition is called pudendal neuralgia. The hallmark symptom is pain in the areas the nerve supplies: the genitals, perineum, or rectal region. This pain typically feels like burning, stabbing, or an electric shock. It can also present as numbness, a feeling of pressure, or the sensation of sitting on a golf ball.
A distinctive feature of pudendal neuralgia is its relationship to posture. Pain worsens with sitting and improves when standing or lying down. Sitting compresses the nerve in Alcock’s canal, intensifying symptoms. Notably, the pain does not typically wake people from sleep, which helps distinguish it from other chronic pain conditions. There is also no objective loss of sensation on examination, even though the nerve pain itself can be severe. These characteristics form the core of the Nantes criteria, the standard diagnostic framework clinicians use to identify pudendal neuralgia.
Common Causes of Injury
The pudendal nerve can be damaged through compression, stretching, or direct trauma. The most common causes include:
- Prolonged sitting: Especially on hard surfaces, which presses the nerve against the bony structures of the pelvis over time.
- Cycling: Chronic pressure from a bicycle seat can cause microtrauma to the nerve and lead to scarring (fibrosis) within the pudendal canal and surrounding ligaments.
- Childbirth: Vaginal delivery stretches the pelvic floor muscles significantly, and the fetal head can compress or stretch the pudendal nerve during passage.
- Pelvic surgery: Procedures to repair pelvic organ prolapse are the most frequently implicated, particularly when surgical mesh is used. Hysterectomy and sling procedures for incontinence can also cause injury.
- Direct trauma: Falls or impacts to the buttocks or lower back can damage the nerve.
- Chronic constipation: Repeated straining increases pressure on the nerve and pelvic floor over time.
How Pudendal Nerve Problems Are Diagnosed
Diagnosis relies on a combination of symptom patterns and a targeted nerve block. The five Nantes criteria are: pain in the territory the pudendal nerve supplies, pain that worsens with sitting, pain that does not wake you at night, no detectable sensory loss on physical exam, and relief from a pudendal nerve block (an injection of local anesthetic near the nerve). All five criteria should be met for a confident diagnosis.
The nerve block itself serves as both a diagnostic tool and a treatment. If numbing the nerve eliminates or significantly reduces the pain, it confirms the pudendal nerve as the source. However, nerve blocks are not always reliable. Up to 50% may fail on at least one side, though the median failure rate is closer to 20%.
Treatment and Management
Initial treatment for pudendal neuralgia focuses on removing the source of compression. That means avoiding prolonged sitting, switching to a cushion with a cutout that relieves pressure on the perineum, and temporarily stopping activities like cycling. Pelvic floor physical therapy can help when muscle tension or spasm is contributing to nerve compression, which it frequently does.
When conservative measures are not enough, nerve blocks with a combination of anesthetic and anti-inflammatory medication can provide weeks to months of relief. Some people need repeated blocks. For cases where the nerve is physically trapped between ligaments or within scar tissue, surgical decompression is an option. The surgeon frees the nerve from the structure compressing it, similar to carpal tunnel release in the wrist. Recovery from decompression surgery is gradual, often taking months, because nerves heal slowly.
The pudendal nerve’s reach across continence, sexual function, and pelvic sensation means that even partial dysfunction can affect multiple areas of daily life simultaneously. Understanding what this nerve does, and where it’s vulnerable, is the first step toward recognizing when something has gone wrong.