Male urethra

Dr Matt A. Morgan and Dr Ian Bickle et al.

The male urethra is a fibromuscular tube that drains urine from the bladder. It has a longer, more complicated, course than the female urethra and is also more prone to pathology.

The male urethra measures, on average, 18-20 cm in length. It commences at the internal urethral orifice in the trigone of the bladder and opens in the navicular fossa of the glans penis at the external urethral meatus, which is the narrowest part of the urethra.

The male urethra can be divided into anterior and posterior portions. The anterior urethra is composed of the penile and bulbar urethra to the level of the urogenital diaphragm. The posterior urethra is composed of the membranous and prostatic urethra.

Anterior urethra
  • penile (spongy, pendulous) urethra (~16 cm long): encased by corpus spongiosum of the penis
    • the longest portion
    • the 'fossa navicularis' is a small normal dilatation of the distal penile urethra
  • bulbar (bulbous) urethra: traverses the root of the penis

The anterior urethra is lined by pseudostratified columnar epithelium. The very distal portion (at approximately the level of the fossa navicularis) is lined by squamous epithelium.

Posterior urethra
  • membranous urethra (1 cm long): passes through the urogenital diaphragm, surrounded by sphincter urethrae
    • the shortest and narrowest portion
  • prostatic urethra (3 cm long): surrounded by the prostate gland; on its posterior wall lies the smooth muscle verumontanum
    • it receives the ejaculatory ducts and numerous small prostatic ducts

The posterior urethra is lined by transtional columnar epithelium.

Fluoroscopy

The division into anterior and posterior urethras is important in terms of pathology and in imaging the urethra: the anterior urethra being visualised by performing a retrograde (ascending) urethrogram and the posterior urethra with an antegrade (descending or micturating) urethrogram.

MRI
  • T2
    • axial: membranous urethra is a low-intensity outer ring surrounding a high-intensity inner epithelium
    • sagittal and coronal images may show the course of the anterior and posterior urethra but often the proximal prostatic and penile urethra are not well seen unless there is an in-dwelling (Foley) catheter

Abdominal and pelvic anatomy
Share article

Article Information

rID: 25563
System: Urogenital
Section: Anatomy
Synonyms or Alternate Spellings:
  • Male urethra anatomy
  • Male urethral anatomy

Support Radiopaedia and see fewer ads

Cases and Figures

  • Drag
    Figure 1
    Drag here to reorder.
  • Drag
    Case 1: normal urethrogram
    Drag here to reorder.
  • Drag
    Case 1: normal urethrogram (annotated)
    Drag here to reorder.
  • Drag
    Rt oblique
    Case 2: as part of a cystourethrogram
    Drag here to reorder.
  • Updating… Please wait.
    Loadinganimation

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.