Internal Pudendal Artery: Anatomy and Role in Sexual Health

The internal pudendal artery is the principal blood vessel supplying the genitals and perineum in both sexes. Branching from the internal iliac artery deep in the pelvis, it follows a winding path out of and back into the pelvic cavity before reaching the erectile tissues of the penis or clitoris, the anal canal, and the surrounding skin and muscles. Because it feeds the structures responsible for erection, continence, and sensation in the pelvic floor, it shows up in an unusually wide range of medical conversations, from prostate cancer surgery and pelvic trauma to pressure-sore reconstruction and even long-distance cycling.

Where It Runs and What It Supplies

The internal pudendal artery originates inside the pelvis as a branch of the internal iliac artery’s anterior division. From there it takes an unusual detour: it exits the pelvis through the greater sciatic foramen, hooks around the ischial spine, and re-enters the pelvis through the lesser sciatic foramen. Once back inside, it travels along the inner wall of the ischial tuberosity in a fascial tunnel called the pudendal canal (or Alcock’s canal), running along the lateral wall of the ischioanal fossa.

Along this course, it throws off several named branches. The inferior rectal artery heads medially to supply the anal canal and the skin around it. The perineal artery supplies the superficial perineal muscles, the bulb of the penis or vestibule, and the posterior scrotal or labial skin. The artery then continues as the common penile artery in males, which further divides into the dorsal artery of the penis, the deep (cavernosal) artery that runs inside the erectile tissue, and the bulbourethral artery. In females, the analogous terminal branches supply the clitoris and the labia. Animal studies confirm that the gross layout in females closely mirrors the male pattern: the internal pudendal artery acts as the primary feeder of clitoral, labial, and vaginal tissue, bifurcating into a posterior labial branch and an anterior clitoral branch that meets its counterpart from the opposite side just behind the pubic symphysis.¹

Why It Matters for Sexual Function

Erection depends on a rapid increase in arterial inflow to the erectile bodies. The internal pudendal artery and its downstream branches are the resistance vessels that control that inflow. When something goes wrong with them, either from atherosclerosis, nerve damage, or structural compression, erection quality suffers. Doppler studies comparing men with and without vascular causes of erectile dysfunction illustrate this clearly: men with normal vascular function showed peak blood-flow velocities in the helicine arteries of roughly 19 cm/s, while men whose erectile dysfunction had a vascular origin had velocities around half that value and could not achieve full rigidity.²

The same vessel plays a parallel role in female arousal. Research describes the internal pudendal arteries as “the key resistance vessels controlling the peripheral circulatory component of sexual responses” in both sexes, though the precise ways the vessel remodels and responds to vasoactive signals differ between males and females, reflecting the different mechanical demands of arousal in each sex.³

Atherosclerosis and Erectile Dysfunction as a Cardiovascular Warning

Because the internal pudendal artery is a small-caliber vessel (roughly 2.7 mm in diameter at its narrowest point), it can develop plaque buildup earlier or more noticeably than larger arteries. This observation has fueled the “artery size” hypothesis of erectile dysfunction: the idea that erectile problems often surface years before a heart attack because the smaller penile arteries clog up sooner than the larger coronary arteries.

A pilot angiographic study found a strong correlation between the presence of coronary artery disease and internal pudendal artery disease. Among the patients with pudendal lesions, average stenosis severity reached about 55–66%, with some patients showing complete unilateral occlusion.⁴ A study of diabetic men with multi-vessel coronary disease found significant internal iliac or pudendal artery disease in about a fifth of them, with the likelihood increasing with age and decreasing kidney function.⁵

The relationship is not perfectly straightforward, though. One study that looked specifically at whether worse erectile dysfunction scores correlated with more severe pudendal artery narrowing found no significant correlation between the two measures.⁶ That disconnect likely reflects the fact that erection depends on nerve function, smooth-muscle health, and hormonal signals in addition to raw blood flow. A moderately narrowed artery might cause no symptoms if everything else is working well, while a man with nerve damage or hormonal deficiency might have severe erectile dysfunction despite open arteries.

What Diabetes Does to This Artery

Diabetes deserves its own mention because it attacks the internal pudendal artery through multiple pathways at once. Animal research has shown that in diabetic subjects, the artery becomes abnormally sensitive to constricting signals. Internal pudendal arteries from diabetic rats constricted far more aggressively in response to endothelin-1 (a potent vessel-tightening molecule) compared with healthy controls, and this exaggerated response was driven in part by the Rho-kinase signaling pathway.⁷ Separate work in diabetic mice found that the artery also suffers from increased oxidative stress, driven by a specific enzyme called NOX1 that generates harmful reactive oxygen species. The arteries from diabetic mice showed roughly 40% greater contraction to stimulatory agents compared with healthy controls.⁸

The clinical takeaway is that diabetes does not just narrow the artery through plaque; it also makes the artery’s muscular wall overreact to constricting signals and underreact to relaxing ones, compounding the blood-flow deficit. This helps explain why erectile dysfunction in diabetic men tends to be more severe and harder to treat than in men whose vascular disease stems from other risk factors alone.

Accessory Pudendal Arteries and Their Surgical Significance

Not everyone’s blood supply to the genitals follows the textbook pattern. Accessory pudendal arteries are extra vessels that reach the penis or clitoris by routes other than the main internal pudendal trunk. They can arise from the obturator artery, the inferior vesical artery, or other pelvic branches and travel along the surface of the prostate, the pubic bone, or the pelvic floor muscles to reach the erectile tissue. A meta-analysis estimated that these vessels most commonly branched from the obturator artery (about half the time) or the inferior vesical artery (about 30% of the time).⁹

A detailed anatomical study of Japanese men undergoing robotic prostatectomy categorized these extra vessels by their location. Among hundreds of accessory arteries observed, the most common types ran along the pubic bone or within the pelvic fascia above the level of the endopelvic fascia, each accounting for roughly 38% of cases. Less common were arteries running along the surface of the prostate or beneath the endopelvic fascia.¹⁰

These accessory vessels matter most during radical prostatectomy for prostate cancer, where the surgeon must remove the prostate gland while trying to spare the nerves and blood vessels that support erection. Whether to preserve accessory pudendal arteries when they are encountered has been debated for decades. An early study found that these arteries were present in only about 4% of patients and that potency rates were similar whether or not they were preserved.¹¹ A later study, however, found that men whose accessory arteries were preserved were more than twice as likely to regain potency and recovered it in about half the time compared with men whose arteries were cut.¹² And a more recent analysis of robot-assisted cases found that transecting these arteries had no measurable effect on erection recovery, regardless of the patient’s age or how many accessory vessels were cut.¹³

The conflicting findings likely reflect how variable each person’s genital blood supply is. In some men, an accessory artery provides the dominant or sole arterial input to the erectile tissue; cutting it would be catastrophic. In others, it is a minor redundant channel whose loss the body barely notices. Surgeons generally try to preserve these vessels when they can do so safely, but the evidence does not support delaying or complicating cancer surgery for the sake of a small accessory artery.

Pelvic Trauma and Emergency Hemorrhage

Severe pelvic fractures, particularly “open book” injuries where the pelvic ring is disrupted anteriorly, can tear pelvic arteries and cause life-threatening hemorrhage. The usual culprits are the posterior branches of the internal iliac system, but the internal pudendal artery can also be the source. A case report described a patient with an open-book fracture whose CT angiogram showed contrast leaking from the right internal pudendal artery, indicating active arterial bleeding. In that particular case, a follow-up catheter angiogram found that the bleed had stopped on its own, but the report emphasized that clinicians managing unstable pelvic fractures should keep the internal pudendal artery on their list of possible bleeding sources.¹⁴

High-Flow Priapism

Blunt trauma to the perineum, such as a straddle injury from falling onto a bicycle crossbar or a kick, can create an abnormal connection between a branch of the internal pudendal artery and the erectile tissue. Blood pours unregulated into the corpora cavernosa, producing a persistent partial erection that, unlike the more dangerous low-flow priapism, is usually painless and does not damage tissue immediately. This is called high-flow or arterial priapism.

The standard treatment involves threading a catheter into the internal pudendal artery and blocking the abnormal connection with embolization material. A study following six patients treated with superselective embolization of the internal pudendal artery found that all six achieved detumescence and maintained normal erectile function at five or more years of follow-up.¹⁵ Using temporary agents like gelatin sponge rather than permanent coils can allow the blocked vessel to reopen over time, preserving long-term blood flow while stopping the priapism. One case report confirmed that temporary gelatin-sponge embolization of the cavernosal artery was safe and effective for exactly this purpose, with the patient retaining erectile function afterward.¹⁶

Radiation Damage After Pelvic Cancer Treatment

Pelvic radiation therapy for prostate, rectal, or cervical cancer can damage the internal pudendal artery, contributing to erectile dysfunction that develops months or years after treatment. Research using stereotactic body radiation therapy in an animal model found that radiation caused a slowing of the systolic rise time in the artery, which corresponded to decreased arterial patency. The artery’s response to vasodilating drugs also became abnormal: papaverine, which normally opens vessels and speeds blood flow, paradoxically slowed it after higher radiation doses, suggesting structural or functional damage to the vessel wall. These changes appeared to be dose-dependent.¹⁷

This finding matters because radiation-induced erectile dysfunction has traditionally been blamed mostly on nerve damage. The evidence that the artery itself becomes structurally abnormal and starts responding paradoxically to vasoactive signals suggests a second, vascular mechanism at work. Clinicians planning radiation fields for pelvic cancers are increasingly trying to limit the dose that reaches the pudendal neurovascular bundle, though how much dose sparing is achievable without compromising cancer control remains an active question.

How Androgen Levels Affect the Vessel

Testosterone does more than drive libido; it helps maintain the structural and functional health of the blood vessels that supply the genitals. Animal studies have shown that androgen deprivation, as occurs during hormonal therapy for prostate cancer, leads to measurable deterioration of the internal pudendal artery. Arteries from castrated rats showed weakened contractions and impaired relaxation responses, along with structural thinning (hypotrophic remodeling) of the vessel wall and increased markers of programmed cell death.¹⁸ This helps explain why men on androgen-deprivation therapy for prostate cancer often develop erectile dysfunction that does not fully resolve even if hormonal therapy is later stopped: the artery itself has remodeled.

Endovascular Treatment for Severe Vascular Erectile Dysfunction

For men whose erectile dysfunction stems from severe atherosclerotic narrowing of the pudendal arteries and who do not respond to oral medications or injections, endovascular revascularization is an emerging option. The idea is similar to coronary angioplasty: a catheter is threaded into the narrowed pudendal artery, and the blockage is opened with a balloon, sometimes with placement of a drug-eluting stent or application of a drug-coated balloon to prevent re-narrowing. A case report described a diabetic patient with severe vasculogenic erectile dysfunction who underwent angioplasty of the pudendal arteries with a drug-coated balloon and drug-eluting stent, combined with injection of the patient’s own blood cells into the erectile tissue. The procedure restored normal erectile function.¹⁹

This remains investigational rather than routine practice. The small caliber of the artery, the tendency for small vessels to re-narrow after intervention, and the lack of large randomized trials mean that pudendal artery angioplasty is currently reserved for patients who have failed all other options. But it signals a shift in thinking: erectile dysfunction caused by arterial disease may eventually be treatable with the same catheter-based tools used for coronary and peripheral artery disease.

Imaging the Internal Pudendal Artery

Diagnosing pudendal artery disease requires seeing the vessel clearly, which is not always easy given its small size and deep, winding course. The traditional gold standard is digital subtraction angiography, where contrast dye is injected through a catheter and X-ray images are taken. A comparative study evaluated CT angiography against this standard for detecting pudendal artery lesions and found that CT angiography had perfect sensitivity (it caught every lesion that angiography found) but lower specificity, meaning it sometimes called a normal artery abnormal. Overall accuracy was about 81%.²⁰ In practice, most initial evaluation relies on penile Doppler ultrasound after injection of a vasodilator, which is less invasive but cannot directly image the pudendal artery itself. Catheter-based angiography is generally reserved for patients being considered for intervention.

Reconstructive Surgery Using Pudendal Artery Perforator Flaps

The internal pudendal artery has found an entirely different clinical role in reconstructive surgery. Small branches (perforators) from the artery pass through the pelvic floor and gluteal muscles to supply the overlying skin of the buttock and perineum. Surgeons can harvest a flap of skin and fat based on these perforators and rotate it to fill defects nearby.

One common application is closing the wound left after abdominoperineal resection, a surgery for low rectal cancer that removes the rectum and anus and leaves a large perineal defect. A series of 11 patients who received internal pudendal artery perforator flaps for this purpose found that all flaps survived with no major immediate complications, even in patients who had received prior radiation therapy.²¹ The same type of flap has also been used for ischial pressure sores, the deep wounds that develop over the sitting bones in wheelchair-bound patients. A cohort study found the flap to be safe and reliable for this purpose, with the advantage of leaving the posterior thigh skin and buttock contour intact, which matters for patients who need to keep sitting on the area.²²

Comparative Anatomy Across Species

The internal pudendal artery is not unique to humans; it is a conserved feature across mammals, though its branching pattern varies in ways that reflect evolutionary relationships. In llamas, for instance, the internal iliac artery divides into the caudal gluteal and internal pudendal arteries at the level of the third sacral vertebra. The visceral pelvic branches (the arteries to the prostate or vagina) arise from the internal pudendal trunk rather than independently from the internal iliac, a pattern that resembles what is seen in cats and dogs rather than in cattle or pigs.²³ A follow-up study comparing the pudendal artery’s distribution in male and female llamas with that in dromedary camels found striking similarities between the two species, providing anatomical evidence supporting their shared evolutionary origin as camelids.²⁴

These comparative studies are not just academic curiosities. Veterinary surgeons operating on pelvic or reproductive structures in animals need the same detailed arterial maps that human surgeons use. And for researchers studying erectile physiology or vascular disease in animal models, knowing exactly how the pudendal arterial tree in rats, mice, or other lab species compares to the human version is essential for interpreting experimental results and translating them to clinical medicine.