Diagnostic Ultrasound - Abdomen and Pelvis

Ureters and Bladder
Anatomy: Pelvis
GROSS ANATOMY
Ureters
• Muscular tubes (25-30 cm long) that carry urine from
kidneys to bladder
○ In abdomen, retroperitoneal location
– Proximal ureters lie in perirenal space
– Mid ureters lie over psoas muscles slightly medial to
tips of L2-L5 transverse process
○ In pelvis, lie anterior to sacroiliac joints crossing common
iliac artery bifurcation near pelvic brim
– Lies anterior to internal iliac vessels, and course along
pelvic sidewall
– At level of ischial spines, ureters curve anteromedially
to enter bladder at level of seminal vesicles (men) or
cervix (women)
– Ureterovesical junction: Ureters pass obliquely
through muscular wall of bladder for ~ 2 cm, creating
valve effect with bladder distension, preventing
vesicoureteral reflux (VUR)
○ 3 points of physiological narrowing: Ureteropelvic
junction, pelvic brim (crossing over the common iliac
artery), and ureterovesical junction
• Vessels, nerves, and lymphatics
○ Arterial branches are numerous and variable, arising
from aorta and renal, gonadal, internal iliac, vesical, and
rectal arteries
○ Venous branches & lymphatics follow arteries with
similar names
○ Innervation
– Autonomic from adjacent sympathetic and
parasympathetic plexuses, cause ureteral peristalsis
– Also carry pain (stretch) receptors; "stone" in
abdominal ureter perceived as back & flank pain; pain
from stone in pelvic ureter may extend to scrotum or
labia
○ Lymphatics to external & internal iliac nodes (pelvic
ureter), aortocaval nodes (abdomen)
Bladder
• Hollow, distensible viscus with strong, muscular wall and
normal adult capacity of 300-600 mL of urine
• Lies in extraperitoneal (retroperitoneal) pelvis
• Peritoneum covers dome of bladder
○ Reflections of peritoneum form deep recesses in pelvic
peritoneal cavity
○ Rectovesical pouch (between rectum and bladder) is
most dependent recess in men (and in women following
hysterectomy)
○ Vesicouterine pouch (bladder and uterus) and
rectouterine pouch (of Douglas; rectum and uterus) are
most dependent in women
• Bladder is surrounded by extraperitoneal fat and loose
connective tissue
○ Perivesical space (contains bladder and urachus)
○ Prevesical or retropubic space (of Retzius) between
bladder and symphysis pubis
– Communicates superiorly with infrarenal
retroperitoneal compartment
– Communicates posteriorly with presacral space
○ Spaces can expand to contain large amounts of fluid (as
in extraperitoneal rupture of bladder and hemorrhage
from pelvic fractures)
• Wall of bladder composed mostly of detrusor muscle
○ Trigone of bladder: Triangular structure at base of
bladder with apices marked by 2 ureteral orifices and
internal urethral orifice
• Vessels, nerves, and lymphatics
○ Arteries from internal iliac
– Superior vesical arteries and other branches of
internal iliac arteries in both sexes
○ Venous drainage
– Men: Vesical & prostatic venous plexuses → internal
iliac and internal vertebral veins
– Women: Vesical and uterovaginal plexuses → internal
iliac vein
○ Autonomic innervation
– Parasympathetic from pelvic splanchnic & inferior
hypogastric nerves (causes contraction of detrusor
muscle and relaxation of internal urethral sphincter to
permit emptying of bladder)
– Sensory fibers follow parasympathetic nerves
IMAGING ANATOMY
Overview
• Normal ureters are small in caliber (2-8 mm) and are nearly
impossible to appreciate on ultrasound largely due to
obscuration by overlying bowel gas
• Fluid-distended urinary bladder is anechoic with posterior
acoustic enhancement
• Urinary bladder changes in shape and position depending
on intraluminal volume of urine
○ In its nondistended state, urinary bladder is retropubic in
location, lying anterior to uterus in females and rectum in
males
○ In markedly distended state, urinary bladder may occupy
abdominopelvic area
○ Urinary bladder wall changes in thickness depending on
state of distension of urinary bladder, and is normally 3-5
mm in thickness
ANATOMY IMAGING ISSUES
Imaging Recommendations
• Transducer: Curvilinear 2-5 MHz
• Ureters
○ Ureters are normally not seen on ultrasound unless they
are dilated; when dilated, overlying bowel gas may still
limit ureteral evaluation in transabdominal approach
– Proximal dilated ureters may be well seen using
kidney as window in coronal oblique plane
– Middle portion of dilated ureter may be identified in
pediatric patients or thin adults using transabdominal
approach
– Dilated terminal ureter/ureterovesical junctions are
seen best along posterolateral aspect of urinary
bladder on transverse view
○ Ureteral caliber may slightly increase as result of
overfilled urinary bladder
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