Transcript 09-Urinary Bladder2008-03

PELVIC VISCERA
 Urinary
bladder, ureter, urethra
 Sigmoid colon, rectum
 Male genital organs: vas deferens,
seminal vesicles, prostate
 Female genital organs: ovaries, Fallopian
tubes, uterus, vagina
Ureters, Urinary Bladder
&
Male Urethra
Ureter

Crosses pelvic inlet in front
of bifurcation of common
iliac artery
 Runs downward in front to
internal iliac artery,
reaches ischial spine
 Turns forward and
medially , enters the upper
lateral angle of urinary
bladder
 Near its termination, is
crossed by the vas
deferens
Ureter cont’d

Passes obliquely through
the wall of bladder for
about ¾ inch before
opening into the bladder
cavity.
 Bladder muscle
contraction mechanically
closes off ureteral orifice
which prevents a reverse
flow of urine toward the
kidney
Ureter cont’d

The ureter has
constrictions at three
points:
 ureteropelvic junction
 crossing of
external/common
iliac artery
 where ureters enter
bladder
 These are also sites of
obstruction and stone
impaction
Urinary Bladder

Located immediately
behind the pubic
symphysis
 Shape and relations vary
according to the amount
of urine it contains
 An empty bladder is
entirely a pelvic organ; as
it fills, rises up into the
hypogastric region
 In young child the empty
bladder projects above
the pelvic inlet
Urinary Bladder cont’d






The empty bladder is
pyramidal in shape
having:
An apex
A base (posterior
surface)
A superior surface
Two infrolateral
surfaces
A neck
Urinary Bladder cont’d
Apex:

Lies behind the upper
margin of the
symphysis pubis
 Urachus passes
upwards to the
umbilicus forming the
median umbilical
ligament
Urinary Bladder cont’d
Base or Posterior
surface:





Triangular in shape
Suprolateral angles
joined by ureters
Inferior angle gives
urethra
Upper part covered by
peritoneum
Lower part related to vas
deferentia and seminal
vesicles, that separate it
from rectum
Urinary Bladder cont’d
Superior surface:
 Completely covered
by peritoneum.
Along its lateral
margin, the
peritoneum is
reflected to the
lateral pelvic wall
 Is related to the coils
of ileum or sigmoid
colon
 As
bladder fills, the
superior surface
bulges upward into
abdominal cavity.
 The peritoneal
lining is peeled off
the lower part of
anterior abdominal
wall and the
bladder comes into
direct contact with
the anterior
abdominal wall
Urinary Bladder cont’d
Infrolateral surfaces:

Related in front to the
retropubic pad of fat &
the pubic bones
 Posteriorly lie in contact
with the obturator
internus above and
levator ani below
Urinary Bladder cont’d
Neck:




Lies inferiorly and rests on
the upper surface of
prostate.
Here, the smooth muscle
fibers of the bladder are
continuous with those of the
prostate
The circular muscle fibers
thickened to form the
sphincter vesicae
Held in place by
puboprostatic ligament (in
male) and pubovesical
ligament (in female), formed
by thickening of the pelvic
fascia
Trigone of the Urinary Bladder

The trigone is a smooth
triangular region on the
internal surface of the base
of bladder, between the
openings of the two ureters
and the urethra
 Superior angles correspond
to openings of ureters and
inferior angle to the
opening of urethra
 Limited above by a
muscular ridge between the
ureteric openings, called
the interureteric ridge
Trigone of the Urinary Bladder cont’d

The mucous membrane is
always smooth even when
the bladder is empty (unlike
rest of mucous membrane
which is thrown into folds in
empty bladder) as it is
firmly adherent to the
underlying muscular coat
(detrusor muscle)
 Uvula vesicae, a small
elevation located just
behind the urethral orifice,
produced by the median
lobe of prostate.
Urinary Bladder
 Arterial
supply: Superior & inferior vesical
arteries, branches of internal iliac artery
 Veins form vesical venous plexus, which
communicates with prostatic plexus and is
drained into the internal iliac vein
 Lymphatics drain into internal & external
iliac lymph nodes
Urinary Bladder: Nerve Supply


The nerves form the vesical
nerve plexus that contains:
 Sympathetic fibers derived
mainly from L1, 2 nerves
 Parasympathetic fibers
derived from pelvic splanchnic
nerves S2,3,4
 Sensory fibers from the
bladder are visceral and
transmit pain sensation
resulting from overdistention
Micturition reflex
Male Urethra

About 8 inches long
 Extending from the
neck of bladder to the
external urinary meatus
on the tip of the glans
penis
 Divided into three
parts:



Prostatic
Membranous
Penile
Prostatic Urethra




Widest and the most
dilatable part of the urethra
About 11/4 inches long
Begins at the neck of the
bladder, becomes
continuous with the
membranous urethra at the
apex of the prostate
Posterior wall shows
urethral crest, prostatic
sinus, prostatic utericle,
openings of the ejaculatory
ducts
Uvula vesicae
Prostatic utericle & openings of
the ejaculatory ducts
Membranous Urethra

About ½ inch long
 Least dilatable part
 Lies within the
urogenital diaphragm
surrounded by the
sphincter urethrae
muscle
Penile (Spongy) Urethra
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About 6 inches long
Enclosed in the bulb and
corpus spongiosum of the
penis
Within the glans penis, it is
dilated to form the fossa
terminalis (navicular fossa)
Receives the openings of the
ducts of the bulbourethral
glands just below the
urogenital diaphragm
External urinary meatus is the
narrowest part of the entire
urethra
navicular
fossa
External urinary meatus
Clinical Notes

Urinary retention
 Suprapubic aspiration
 Ureteric stones:
impaction at the
constrictions
FLY
HIGH