Muscular tubes (25-30 cm long) that carry urine from kidneys to bladder

Course

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  In abdomen, retroperitoneal location

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    Proximal ureters lie in perirenal space

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    Mid ureters lie over psoas muscles slightly medial to tips of L2-L5 transverse process

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  In pelvis, lie anterior to sacroiliac joints crossing common iliac artery bifurcation near pelvic brim

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    Lie anterior to internal iliac vessels and course along pelvic sidewall

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    At level of ischial spines, ureters curve anteromedially to enter bladder at level of seminal vesicles (men) or cervix (women)

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  Ureterovesical junction (UVJ) : Ureters pass obliquely through muscular wall of bladder for ~ 2 cm

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    Creates valve effect with bladder distension, preventing vesicoureteral reflux (VUR)

3 points of physiological narrowing

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  Ureteropelvic junction

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  Pelvic brim (crossing over common iliac artery)

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  UVJ

Vessels, nerves, and lymphatics

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  Arterial branches are numerous and variable, arising from aorta and renal, gonadal, internal iliac, vesicle, and rectal arteries

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  Venous branches and lymphatics follow arteries with similar names

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  Innervation

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    Autonomic from adjacent sympathetic and parasympathetic plexuses

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      Responsible for ureteral peristalsis

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    Also carry pain (stretch) receptors

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      Stone in abdominal ureter perceived as back and flank pain

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      Stone in pelvic ureter may project to scrotum or labia

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  Lymphatics to external and internal iliac nodes (pelvic ureter), aortocaval nodes (abdomen)

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

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  Reflections of peritoneum form deep recesses in pelvic peritoneal cavity

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  Rectovesical pouch (between rectum and bladder) is most dependent recess in men (and in women following hysterectomy)

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  Vesicouterine pouch (between bladder and uterus) and rectouterine pouch of Douglas (between rectum and uterus)

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    Rectouterine pouch most dependent in women

Bladder is surrounded by extraperitoneal fat and loose connective tissue

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  Perivesical space (contains bladder and urachus)

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  Prevesical or retropubic space (of Retzius) between bladder and symphysis pubis

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    Communicates superiorly with infrarenal retroperitoneal compartment

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    Communicates posteriorly with presacral space

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  Spaces can expand to contain large amounts of fluid (as in extraperitoneal rupture of bladder and hemorrhage from pelvic fractures)

Bladder wall composed mostly of detrusor muscle

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  Trigone of bladder: Triangular structure at base of bladder with apices marked by 2 ureteral orifices and internal urethral orifice

Vessels, nerves, and lymphatics

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  Arteries from internal iliac

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    Superior vesicle arteries and other branches of internal iliac arteries in both sexes

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  Venous drainage

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    Men: Vesicle and prostatic venous plexuses → internal iliac and internal vertebral veins

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    Women: Vesicle and uterovaginal plexuses → internal iliac vein

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  Autonomic innervation

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    Parasympathetic from pelvic splanchnic and inferior hypogastric nerves (causes contraction of detrusor muscle and relaxation of internal urethral sphincter to permit emptying of bladder)

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    Sensory fibers follow parasympathetic nerves

Normal ureters are small in caliber (2-8 mm) and are difficult to appreciate on ultrasound

Fluid-distended urinary bladder is anechoic with posterior acoustic enhancement

Urinary bladder changes in shape and position depending on intraluminal volume of urine

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  In its nondistended state, urinary bladder is retropubic in location, lying anterior to uterus in females and rectum in males

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  In markedly distended state, urinary bladder may occupy abdominopelvic area

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  Urinary bladder wall changes in thickness depending on state of distension of urinary bladder and is normally 3-5 mm in thickness

Transducer: Curvilinear 2-5 MHz

Ureters

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  Ureters are normally not seen on ultrasound unless they are dilated; when dilated, overlying bowel gas may still limit ureteral evaluation in transabdominal approach

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    Proximal dilated ureters may be well seen using kidney as window in coronal oblique plane

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    Middle portion of dilated ureter may be identified in pediatric patients or thin adults using transabdominal approach

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    Dilated terminal ureter/UVJ are seen best along posterolateral aspect of urinary bladder on transverse view

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      Can also be evaluated by endovaginal sonography in women

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  Ureteral caliber may slightly increase as result of overfilled urinary bladder

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    Distended bladder may cause ureteral and pelvicalyceal dilation, and rescanning post void is beneficial to exclude obstruction

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  Color Doppler

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    Assess ureteral jets; presence of jets helps exclude complete ureteral obstruction

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    Look for twinkling artifact from obstructing stone

Bladder

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  Recommend fluid intake prior to examination to ensure optimal distension of urinary bladder

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    In fully distended state, urinary bladder is easily visualized using transabdominal approach

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  Examine patient in supine position with transabdominal suprapubic approach

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    Perform scanning in sagittal and transverse planes

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    Patient may be placed in decubitus position to determine mobility and differentiated intravesical masses from debris or stones

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    With poor distention, caudal transducer angulation is needed to visualize urinary bladder in its retropubic location

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  Nature of cystic structure in pelvis may be ascertained by asking patient to void or by inserting Foley catheter

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  Transvaginal ultrasound may be used in women for evaluation of suspect bladder neck lesions, UVJ stone, or ureterocele

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  Advantages of ultrasound

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    Radiation-free, real-time assessment with high spatial resolution of bladder and bladder wall

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    Real-time assessment of intraluminal masses in bladder for mobility and vascularity

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    Real-time imaging guidance for bladder intervention, e.g., placement of percutaneous suprapubic catheters

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    Real-time assessment of ureteral jets using color Doppler imaging; particularly useful in pregnant patients with dilated collecting system

Reverberation artifacts are commonly encountered behind anterior wall of urinary bladder

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  Appear as regularly spaced lines at increasing depth as result of repeated reflection of ultrasound signals between highly reflective interfaces close to transducer

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  May be reduced or avoided by changing scanning angle or by moving transducer or using spacer

Underdistended bladder may give false impression of wall thickening and limits intraluminal assessment

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  Have patient drink water and rescan with better distention

Large midline ovarian or pelvic cystic mass may simulate bladder on transabdominal ultrasound

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  Attention to normal bladder shape, rescanning after voiding to confirm empty bladder, or transvaginal imaging is helpful to differentiate

Ureters are at high risk of inadvertent injury during abdominal or gynecological surgery due to close proximity to uterine (in uterosacral ligament) and gonadal arteries (at pelvic brim)

Ectopic ureter

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  Usually (80%) associated with complete ureteral duplication; more common in females

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  In complete duplication, upper moiety inserts ectopically inferiorly and distally to lower moiety ( Weigert-Meyer rule ) and can be associated with ureterocele

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    Ureterocele may cause obstruction of upper pole moiety; also distorts UVJ of normally inserting lower pole moiety causing predisposition to VUR

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  Ectopic ureteral insertion in females can occur in urethra or vagina, leading to urinary incontinence

Ureterocele

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  Cystic dilation of intramural portion of ureter bulging into bladder

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    Orthotopic: Normal insertion of single ureter

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    Ectopic: Inserts below trigone, mostly in duplicated system

Ureteral duplication

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  Bifid ureter drains duplex kidney, but ureters unite before entering bladder

Urachal anomalies

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  Patent fetal urachus forms conduit between umbilicus and bladder

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  Urachus is normally obliterated to form median umbilical ligament

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  May persist as cyst, diverticulum, or, rarely, fistula

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  Risk of infection or carcinoma (adenocarcinoma)

Bladder diverticula are common

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  Congenital: Hutch diverticulum (near UVJ)

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  Acquired (usually due to chronic bladder outlet obstruction), associated with trabeculated bladder wall

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  Can lead to infection, stones, tumor

Trauma

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  Extraperitoneal bladder rupture

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    Urine and blood distend prevesical space (Retzius)

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    Urine often tracks posteriorly into presacral space, superiorly into retroperitoneal abdomen

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    High association with pelvic fractures

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  Intraperitoneal bladder rupture

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    Urine flows up paracolic gutters into peritoneal recesses and surrounds bowel

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    Bladder ruptures along dome, which is in contact with intraperitoneal space

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    Usually caused by blunt trauma to overdistended bladder