urethra to make its way out the urethral opening.
BLADDER CATHETERIZATION, CYSTOSCOPY, ureteroscopy,
and intravesical therapies use the urethra to enter
the urinary system (usually with sedation or ANES-
THESIA, except catheterization).
In a woman the urethra is about an inch and a
half long, extending from the base of the bladder
to the external GENITALIAwhere it exits the body
between the CLITORISand the VAGINA. The urethra’s
only role in a woman is to carry urine from the
body. In a man the urethra is about eight inches
long and extends from the base of the bladder to
exit the body at the tip of the PENIS. As it exits the
bladder in a man the urethra passes through the
PROSTATE GLAND, which encircles the neck of the
bladder. The male urethra also carries SPERMdur-
ing EJACULATION. The VAS DEFERENS, the tube that
carries SEMENfrom the male reproductive organs,
enters the urethra at the prostate gland. A valve at
the base of the urethra directs the flow of either
urine or semen through the urethra.
For further discussion of the urethra within the
context of the urinary system’s structure and
function please see the overview section “The Uri-
nary System.”
See also EPISPADIAS; HYPOSPADIAS; RETROGRADE
EJACULATION.
urethral stricture Narrowing of the URETHRA,
impeding the passage of URINEfrom the BLADDERto
the outside of the body. Urethral stricture may be
congenital (present at birth) or acquired such as
through scarring resulting from repeated URETHRI-
TIS, BLADDER CATHETERIZATION, and other irritations
to the urethra. BENIGN PROSTATIC HYPERPLASIA(BPH)
andPROSTATITISalso can cause urethral stricture in
men.
Symptoms of urethral stricture include
- straining when urinating
- the sensation that the bladder does not empty
with URINATION(URINARY RETENTION) - diminished urine flow
- frequent URINARY TRACT INFECTION(UTI)
The diagnostic path begins with urinalysis to
determine whether INFECTION is present. Further
diagnostic procedures may include CYSTOSCOPYto
examine the urethra and bladder, INTRAVENOUS
PYELOGRAM(IVP) to assess the flow of BLOODand
urine through the urinary system, or COMPUTED
TOMOGRAPHY(CT) SCANor ULTRASOUNDto visualize
the structures of the lower pelvis. Treatment tar-
gets the identified cause and may include ANTIBI-
OTIC MEDICATIONS when infection is present in
addition to other therapies. Such therapies often
include cystoscopic surgery to cut away SCARtissue
within the urethra or open surgery (urethro-
plasty) to reconstruct a badly scarred or damaged
urethra. These methods permanently restore the
flow of urine through the urethra and have mini-
mal complications or risks.
See also UROLITHIASIS.urethritis INFLAMMATIONof an URETER. INFECTION,
typically a sexually transmitted disease (STD), is
the most common cause of urethritis though ure-
thritis may occur as a result of inflammation or
irritation from trauma such as occurs with BLADDER
CATHETERIZATIONor CYSTOSCOPY. Traumatic urethritis
improves rapidly when the source of the trauma is
gone, often without further treatment. Urologists
classify infectious urethritis as gonococcal urethri-
tis (GU) or nongonococcal urethritis (NGU).
Symptoms may be vague and transient (disappear
in a few days) or nonexistent, though the infec-
tion remains. In about 40 percent of women, ure-
thritis progresses to PELVIC INFLAMMATORY DISEASE
(PID) and INFERTILITY. Repeated or untreated ure-
thritis in men may destroy testicular tissue, result-
ing in sterility. As well, untreated urethritis in
men or women remains contagious through sex-
ual contact.Symptoms and Diagnostic Path
Often urethritis does not have symptoms, particu-
larly in women. When symptoms are present they
typically include- puslike or bloody discharge from the PENIS
- PAINor burning with URINATION(DYSURIA)
Laboratory analysis of discharge or swabs of the
interior of the urethra identify the responsible
PATHOGEN. Generally no further diagnostic proce-222 The Urinary System