Urethra (male) !
The male urethra is the long tube that runs from the bladder through the prostate and the penis; it carries urine and, at ejaculation, semen.
Official name: Male urethra
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What it is
The male urethra, about 18-20 cm long, from the bladder neck to the tip of the glans, in three parts: prostatic, membranous and spongy.
What it does
Carries urine out and, at ejaculation, semen; its sphincters keep it closed between voids.
Key facts
- Where
- About 18–20 cm from the internal urethral orifice to the external meatus; parts: prostatic, membranous, spongy (some texts add a preprostatic part at the bladder neck)
- Blood supply
- Prostatic part: inferior vesical artery; membranous and spongy parts: artery of the bulb, urethral and dorsal arteries (internal pudendal)
- Nerve
- Prostatic plexus (autonomic; internal sphincter); pudendal nerve (S2–S4) to the external sphincter and mucosal sensation
- Function
- Conveys urine and semen; internal sphincter at the bladder neck prevents retrograde ejaculation; external sphincter gives voluntary continence
Relations
- Course
- From the internal urethral orifice at the bladder neck down through the prostate, through the external urethral sphincter and the perineal membrane, forward in the bulb of the corpus spongiosum and along the penis to the meatus on the glans penis
How to find it
Its penile course is followed along the underside of the shaft, from the meatus at the tip of the glans back to the bulb, which sits in the midline just in front of the perineal body. Higher up it passes behind and below the pubic symphysis, where only a catheter, a urethroscope or the finger in the rectum reaches it.
Examination
- Urine flow test (uroflowmetry): a low, flat, plateau-shaped curve suggests a stricture; a low curve of normal shape suggests prostatic obstruction or a weak bladder
On imaging
Retrograde urethrography shows the anterior urethra; voiding cystourethrography shows the posterior urethra; together they map strictures and injuries. Urethroscopy shows the lining directly.
Common problems
- Urethral stricture: a narrowing from scarring after infection, injury or instruments.
- Urethritis, often a sexually transmitted infection (burning when passing urine, discharge).
- Its length and two bends make a catheter harder to pass than in women.
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
- Catheterization: resistance at the meatus or the membranous part is common; resistance at the bladder neck suggests BPH or a bladder neck contracture; suspected urethral injury calls for a suprapubic route
- Posterior injuries (pelvic fracture, membranous part) leak into the pelvis around the bladder; anterior injuries (straddle fall, bulbar part) leak into the perineum under Colles fascia
- Retrograde ejaculation follows when the bladder neck fails to close, as after TURP or with diabetic neuropathy
Development
Above the perineal membrane it comes from the urogenital sinus (endoderm); the penile part forms as the urethral folds close along the underside of the genital tubercle, and incomplete closure leaves hypospadias.
Related conditions
Test yourself
Think of the answer, then tap the question to see it.
Where is the male urethra divided into posterior and anterior parts, and what does each include?
At the perineal membrane: posterior = prostatic and membranous; anterior = bulbar and penile. Injury and stricture patterns follow this split.
What are the two bends of the flaccid male urethra, and how is one straightened for catheterisation?
A fixed subpubic curve and a mobile prepubic curve; lifting the penis straightens the prepubic curve.
What is the narrowest point of the male urethra?
The external meatus, followed by the membranous part; the widest are the prostatic part, the bulb and the navicular fossa.
On uroflowmetry, what does a low, flat, plateau-shaped curve suggest?
A urethral stricture; a low curve of normal shape suggests prostatic obstruction or a weak bladder.
What causes retrograde ejaculation through the male urethra?
Failure of the internal sphincter at the bladder neck to close, as after TURP or with diabetic neuropathy.
Educational information, not medical advice. For any symptom, see a health professional.
Its names
- Official Latin (TA2)
- urethra masculina
- Official Spanish (DeCS)
- Uretra masculina
- English (TA2)
- Male urethra
Related
Sources: Anatomy, Abdomen and Pelvis, Male Genitourinary Tract; Anatomy, Abdomen and Pelvis, Sphincter Urethrae; 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 (OpenStax (Rice University), 2022) · adapted, CC BY 4.0.
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Representative model, for educational purposes only.