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Obstruction of urine flow by
an enlarged prostate gland is a common condition. Over 500,000 TURP procedures
are performed in the United States each year and this number is expected to increase
with the increasing age of the population. Almost 50% of the male population above
age 50 will have some clinical evidence of prostate enlargement. Surgery to relieve
the bladder obstruction has been described since the early 19th century, but the
development of lighted telescopes and electric probes in the late 20th century
has led to the development of the modern TURP.
Anatomy & Physiology
- The prostate gland is
shaped like an inverted cone and lies just below the neck of the urinary bladder.
It is about 5 cm (3 inches) long and 3-4cm wide. The urethra (see Prostatectomy
and Urinary Cystectomy),
which runs from the bladder through the middle of the prostate gland and through
the penis, carries urine from the bladder. (Figure 1 and 2)
- The smooth muscle of
the urethra is the internal urinary sphincter. Just below the prostate gland
is a muscular diaphragm that acts as the external urinary sphincter. This
sphincter, which encircles the urethra, is under both reflex and voluntary
control
- Along the back wall of
the urethra in the prostate, there is an elevation called the verumontanum,
and it is into this elevation that sperm (through the ejaculatory ducts) and
spermatic secretions from the seminal vesicles and prostate enter the urethra
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| Figure 1 - Anatomy
of the prostate gland in relation to the surrounding structures. Note that
the prostate lies below the bladder. The urethra passes from the bladder
through the prostate and penis.© A. Bhandary |
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| Figure 2 - Cross-section
through the bladder and prostate gland. Note that secretions from the prostate
gland and sperm from the ejaculatory ducts mix together in the urethra as
it passes through the bladder. © A. Bhandary |
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