[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Pelvis · Male](https://durgical.com/en/anatomy/region/pelvis/) › Membranous urethra [Urinary system](https://durgical.com/en/anatomy/system/urinary-system/) · [Pelvis · Male](https://durgical.com/en/anatomy/region/pelvis/) # Membranous urethra The membranous urethra is the short part of the [male urethra](https://durgical.com/en/anatomy/male-urethra/) just below the prostate; the external sphincter around it gives voluntary control of urine. Official name: Intermediate part of male urethra [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=pelvis&variant=male&select=membranous_urethra&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The short (about 1-2 cm), narrowest and least stretchy part, from the apex of the prostate through the perineal membrane, surrounded by the [external urethral sphincter](https://durgical.com/en/anatomy/female-external-urethral-sphincter/). ## What it does Where voluntary control of urine happens; after a radical prostatectomy it is joined to the bladder neck, and keeping its length helps continence. ## Key points - Fixed by the perineal membrane and the prostatic attachments above it, it is the segment sheared in pelvic ring fractures (posterior urethral injury) - With the perineal membrane intact, urine and blood from a posterior injury spread upward into the extraperitoneal [pelvis](https://durgical.com/en/anatomy/region/pelvis/) around the bladder, not into the perineum - Erectile dysfunction is common after pelvic-fracture urethral injury because the cavernous nerves and arteries pass right beside this segment ## Key facts **Where** About 1–2 cm from the prostatic apex through the deep perineal pouch and perineal membrane; the narrowest and least distensible part after the external meatus **Attaches** Surrounded by the external urethral sphincter (striated, [pudendal nerve](https://durgical.com/en/anatomy/pudendal-nerve/) S2–S4); bulbourethral glands on each side **Function** Voluntary continence; torn in pelvic fracture (blood at the meatus, high-riding prostate), so the injury is ruled out before a catheter is passed ## Relations **Above** Prostatic apex and the [prostatic urethra](https://durgical.com/en/anatomy/prostatic-urethra-seminal-colliculus/) **Below** [Perineal membrane](https://durgical.com/en/anatomy/perineal-membrane/), below which it becomes the bulbar part of the [spongy urethra](https://durgical.com/en/anatomy/spongy-urethra/) **Lateral** [Bulbourethral glands](https://durgical.com/en/anatomy/bulbo-urethral-gland/), within the deep perineal pouch **In front** Deep dorsal vein of the penis passing under the [pubic symphysis](https://durgical.com/en/anatomy/pubic-symphysis/) to the prostatic venous plexus **Behind** [Perineal body](https://durgical.com/en/anatomy/perineal-body/) and the [rectum](https://durgical.com/en/anatomy/rectum/); a rectourethral fistula is a rare complication of [prostate](https://durgical.com/en/anatomy/prostate/) surgery or radiation ## How to find it Sits at the level of the perineal membrane, just behind and below the pubic symphysis, wrapped by the external urethral sphincter. On digital rectal examination the bulb and this segment are met first in front, and the prostate a few centimetres higher; after a pelvic fracture a prostate that feels high or is not felt classically points to a tear here. ## On imaging When injury is suspected, a retrograde urethrogram is done before any urethral catheter: contrast leaking at this level confirms a posterior injury and shows whether it is partial or complete. Leak above the perineal membrane fills the pelvis; leak below it reaches the perineum. ## Common problems - The part most easily torn in a pelvic fracture. ## How it is diagnosed Urine tests and swabs; urine flow test; urethrogram or a scope (urethroscopy). ## Treatment - Antibiotics for urethritis; widening or surgical repair (urethroplasty) of a stricture. ## Clinical notes - In complete disruption, urine is diverted with a suprapubic catheter; the gap heals with scar and is usually repaired later by urethroplasty - The usual point of resistance when a catheter is passed in a tense patient, as the sphincter contracts around it - Radical prostatectomy joins it to the bladder neck; the length kept and the health of the external urethral sphincter largely decide continence ## Development Comes from the pelvic part of the urogenital sinus (endoderm), as does the prostatic urethra above it. ## Related conditions - [Bladder and urethral injury](https://durgical.com/en/conditions/bladder-and-urethral-injury/) ## Test yourself Think of the answer, then tap the question to see it. ## Which part of the male urethra is sheared in pelvic ring fractures, and why? The membranous urethra, fixed by the perineal membrane and the prostatic attachments above it. ## Which signs suggest membranous urethral injury, and what test comes before any catheter? Blood at the meatus and a high-riding prostate; a retrograde urethrogram is done first. ## Where do urine and blood spread after a membranous urethral injury with an intact perineal membrane? Upward into the extraperitoneal pelvis around the bladder, not into the perineum. ## Why is erectile dysfunction common after pelvic-fracture injury of the membranous urethra? The cavernous nerves and arteries pass right beside the membranous urethra. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/intermediate-part-of-male-urethra/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** pars intermedia urethrae masculinae **Official Spanish (DeCS)** Porción intermedia (membranosa) de la uretra masculina **English (TA2)** Intermediate part of male urethra ## Related - [Prostatic urethra](https://durgical.com/en/anatomy/prostatic-urethra-seminal-colliculus/) - [Spongy urethra](https://durgical.com/en/anatomy/spongy-urethra/) - [External urethral sphincter](https://durgical.com/en/anatomy/female-external-urethral-sphincter/) - [Perineal membrane](https://durgical.com/en/anatomy/perineal-membrane/) - [Bulbourethral glands](https://durgical.com/en/anatomy/bulbo-urethral-gland/) Sources: [Anatomy, Abdomen and Pelvis, Male Genitourinary Tract](https://www.ncbi.nlm.nih.gov/books/NBK562291/); [Anatomy, Abdomen and Pelvis, Sphincter Urethrae](https://www.ncbi.nlm.nih.gov/books/NBK482438/); Anatomy of the Human Body (20th ed.): Surface Markings of the Perineum (Lea & Febiger (Gray's Anatomy, 1918), 1918) · adapted, Public domain; [25.2 Gross Anatomy of Urine Transport](https://openstax.org/books/anatomy-and-physiology-2e/pages/25-2-gross-anatomy-of-urine-transport) (OpenStax (Rice University), 2022) · adapted, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). ## **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/intermediate-part-of-male-urethra/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/intermediate-part-of-male-urethra/