[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Spine](https://durgical.com/en/anatomy/region/spine/) › Pudendal nerve [Nervous system](https://durgical.com/en/anatomy/system/nervous-system/) · [Spine](https://durgical.com/en/anatomy/region/spine/) # Pudendal nerve The pudendal nerve comes from S2-S4 and curves into the perineum; it supplies the [pelvic floor](https://durgical.com/en/anatomy/levator-ani/), the sphincters and genital and anal feeling. [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=spine&select=pudendal_nerve&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A nerve from S2-S4 that leaves the pelvis and curves into the perineum. ## What it does Supplies the pelvic floor, the sphincters and feeling in the genital and anal area. ## Key points - Leaves the [pelvis](https://durgical.com/en/anatomy/region/pelvis/) below the piriformis, curves around the sacrospinous ligament next to the ischial spine and re-enters through the lesser sciatic foramen - Pudendal block: the needle is aimed just medial to and behind the ischial spine through the sacrospinous ligament, through the [vagina](https://durgical.com/en/anatomy/vagina/) or the perineum; used in the second stage of labour and perineal repair - Pudendal neuralgia: burning perineal pain worse sitting, eased standing or lying, that does not wake the person, without objective numbness (Nantes criteria) ## Key facts **Roots** Ventral rami of S2–S4; leaves pelvis via greater sciatic foramen, enters perineum via lesser sciatic foramen, in the pudendal (Alcock) canal **Moves** [External anal sphincter](https://durgical.com/en/anatomy/external-anal-sphincter/), [external urethral sphincter](https://durgical.com/en/anatomy/female-external-urethral-sphincter/), perineal muscles, part of levator ani **Feeling from** Penis or clitoris (dorsal nerve), perineum, posterior [scrotum](https://durgical.com/en/anatomy/scrotum/) or labia, anal canal below the pectinate line ## Relations **Course** Leaves through the greater sciatic foramen below the [piriformis](https://durgical.com/en/anatomy/piriformis-muscle/), crosses behind the [sacrospinous ligament](https://durgical.com/en/anatomy/sacrospinous-ligament/) at the ischial [spine](https://durgical.com/en/anatomy/region/spine/), enters the perineum and runs in the pudendal canal, giving the inferior rectal nerve, then the perineal nerve and the dorsal nerve of the penis or [clitoris](https://durgical.com/en/anatomy/clitoris/) **Behind** At the ischial spine, the [sacrotuberous ligament](https://durgical.com/en/anatomy/sacrotuberous-ligament/); the nerve lies between the two ligaments, a known site of entrapment **Lateral** In the pudendal canal, the [obturator internus](https://durgical.com/en/anatomy/obturator-internus/) and its fascia, which forms the canal **Medial** The ischioanal fossa and its fat; the [anal canal](https://durgical.com/en/anatomy/anal-canal/) ## How to find it It cannot be felt directly. On transgluteal ultrasound or CT it lies at the level of the ischial spine, between the sacrospinous and sacrotuberous ligaments, usually just medial to the [internal pudendal artery](https://durgical.com/en/anatomy/internal-pudendal-artery/), whose Doppler signal guides the needle. ## Examination - Pressure over the ischial spine on vaginal or rectal examination reproducing the pain supports pudendal entrapment - Diagnostic pudendal block: pain relief supports pudendal neuralgia (one of the Nantes criteria) - Anal wink and bulbocavernosus reflexes (S2–S4): absent with pudendal nerve or sacral root damage ## On imaging Not seen on routine imaging; it is located by the ischial spine and the sacrospinous ligament, with the internal pudendal vessels beside it, and then in the pudendal (Alcock) canal on the side wall of the ischioanal fossa. CT, fluoroscopy or ultrasound guide a pudendal block at the ischial spine. Pelvic MRI is used to exclude other causes of pain, such as a mass, rather than to show the nerve. ## Clinical notes - Entrapment sites: between the sacrospinous and sacrotuberous ligaments or in the pudendal canal; long cycling and prolonged sitting are typical triggers - Stretch injury in childbirth (long second stage, instrumental delivery, large baby) and chronic straining can damage it, contributing to faecal incontinence - Traction on an orthopaedic table with a perineal post can cause a temporary pudendal palsy (perineal or penile numbness) after hip or [femur](https://durgical.com/en/anatomy/femur/) surgery - In sacrospinous ligament fixation for vaginal prolapse, sutures are kept well medial to the ischial spine to avoid the nerve and the internal pudendal vessels ## Anatomical variants - Its size, path and branching vary considerably; the inferior rectal nerve may arise separately from the sacral plexus ## Related conditions - [Stress urinary incontinence](https://durgical.com/en/conditions/stress-urinary-incontinence/) - [Obstetric perineal tears and anal sphincter injury](https://durgical.com/en/conditions/obstetric-perineal-tears-and-anal-sphincter-injury/) - [Rectal prolapse](https://durgical.com/en/conditions/rectal-prolapse/) - [Erectile dysfunction](https://durgical.com/en/conditions/erectile-dysfunction/) ## Test yourself Think of the answer, then tap the question to see it. ## From which roots does the pudendal nerve arise, and which canal does it run in? Ventral rami of S2–S4; it runs in the pudendal (Alcock) canal, formed by the obturator internus fascia. ## What is the path of the pudendal nerve out of the pelvis and into the perineum? Out through the greater sciatic foramen below the piriformis, around the sacrospinous ligament at the ischial spine, and in through the lesser sciatic foramen. ## What is the landmark for a pudendal nerve block? The ischial spine: the needle is aimed just medial to and behind it, through the sacrospinous ligament. ## What is the typical pain of pudendal neuralgia? Burning perineal pain, worse sitting and eased standing or lying, that does not wake the person, without objective numbness. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/pudendal-nerve/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** nervus pudendalis TA2 6554 **Official Spanish (DeCS)** Nervio pudendo DeCS D060525 **English (TA2)** Pudendal nerve **Also called** nervus pudendus · plexus pudendus · plexus pudendalis ## Related - [Pelvic floor](https://durgical.com/en/anatomy/levator-ani/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=54423&filter=ths_termall&q=Nervio%20Pudendo); [Anatomy, Abdomen and Pelvis, Pudendal Nerve](https://www.ncbi.nlm.nih.gov/books/NBK554736/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/pudendal-nerve/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/pudendal-nerve/