2. Male urethra
• Gross anatomy
• 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.
3. • The posterior urethra is
composed of the membranous
and prostatic urethra.
4.
5. 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
• it receives the ducts from the bulbourethral glands and the glands of Littré
• 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.
6. 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 runs the urethral crest and the prominent smooth
muscle verumontanum
• the verumontanum receives the prostatic utricle in the midline and
the ejaculatory ductsjust distal to the prostatic utricle; on either side of it lie
the prostatic sinuses, where numerous small prostatic ducts drain
• The posterior urethra is lined by transitional columnar epithelium.
7.
8.
9.
10. URETHROGRAPHY
• Refers to the radiographic study of the urethra using iodinated
contrast media and is generally carried out in males.
11. Terminology
• When the urethra is studied with instillation of contrast into the
distal/anterior urethra it has been referred to as:
1. retrograde urethrography (RUG)
2. ascending urethrography (ASU)
12. • When the posterior urethra is studied during micturition, this has
been referred to as:
1. voiding cystourethrography (VCUG)
2. descending urethrography
3. micturating urethrography
19. Technique
1. Patient supine
2. The catheter is connected to a 50 ml syringe containing contrast medium
and flushed to eliminate air bubbles
3. Using aseptic technique the tip of the catheter is inserted so that the
balloon lies in the fossa navicularis (i.e. immediately proximal to the
meatus within the glans) and its balloon is inflated with 2–3 ml of water
to anchor the catheter and occlude the meatus
4. Contrast medium is injected under fluoroscopic control and steep (30–
45°) oblique films taken. Gentle traction on the catheter is used to
straighten the penis over the ipsilateral leg and prevent urethral overlap
or foreshortening from obscuring pathology.
20. • Depending on the clinical indication, ascending urethrography may be
followed by descending micturating cystourethrography to
demonstrate the proximal urethra and bladder, assuming there is no
contraindication to bladder catheterization, e.g. false passage,
stricture. It may be possible to fill the bladder retrogradely via the
urethral catheter if the patient is able to relax the bladder neck (and
thus avoid bladder catheterization).
22. Complications due to the technique
• Acute urinary tract infection
• Urethral trauma
• Intravasation of contrast medium, especially if excessive pressure is
• used to overcome a stricture.
Normal urethral anatomy. a Retrograde urethrogram shows the anatomical landmarks. The verumontanum is seen as triangular structure in the posterior prostatic urethra (short black arrow). The bulbar cone (distal membranous urethra) is important to identify, to assess disease and plan urologic procedures (long black arrow). b Voiding cystourethrogram shows the normal urethral segments with wide bladder neck (black arrow) during voiding
