Urinary: Urethra Flashcards

1
Q

What are the anatomical segments of the male urethra?

A
  • Anterior (penile and bulbar segments)
  • Posterior (membranous and prostatic)
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2
Q
A

Fossa navicularis

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3
Q
A

Verumontanum (an ovoid mound along the posterior wall of the prostatic urethra that receives the ejaculatory ducts and also contains the prostatic utricle)

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4
Q

Prostatic utricle

A

A embryologic mullerian duct remnant located on the verumontanum of the prostatic urethra

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5
Q

Which portions of the urethra are best evaluated with a retrograde urethrogram?

A

The anterior urethra (penile and bulbar segments)

Note: A voiding/anterograde urethrogram is usually done to visualize posterior urethral problems. It is possible to opacify the entire urethra during a retrograde urethrogram, but this requires applying enough pressure to overcome the normal spasms that occur in the urethra.

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6
Q

The purple portion of urethra is the…

A

Prostatic urethra

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7
Q

The green part of the urethra is the…

A

Membranous urethra

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8
Q

The red part of the urethra is the…

A

Bulbar urethra

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9
Q

The blue part of the urethra is the…

A

Penile urethra

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10
Q

How can you identify the bulbar-membranous junction on a retrograde cystourethrogram?

A

Look for the cone shaped appearance of the proximal bulbar urethra

Note: This is an important junction because it separates the anterior urethra from the posterior urethra.

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11
Q
A
  1. Prostatic urethra
  2. Membranous urethra
  3. Bulbar urethra
  4. Penile urethra
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12
Q

How can you approximate the bulbar-membranous junction of a retrograde urethrogram if you can’t opacify the urethra?

A

Draw a line connecting the inferior margins of the obturator foramina

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13
Q

How can you differentiate the bulbar and penile urethra on a retrograde urethrogram?

A

There should be a turn at this point due to the penis changing angles as it becomes an external structure

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14
Q

Blood in the urethral meatus s/p trauma…

A

Possible urethral injury, recommend a retrograde cystourethrogram

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15
Q

Common causes of traumatic urethral injury

A
  • Straddle injury, such as smash into bicycle seat (usually an anterior urethral injury)
  • MVC or other more intense trauma (usually a posterior urethral injury with associated pelvic fractures/bladder rupture)
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16
Q

Male urethral injury classification

A
  • Type 1(stretched urethra, normal urethrogram)
  • Type 2 (tear of the membranous urethra)
  • Type 3 (tear of the membranous and bulbar urethra)
  • Type 4 (Bladder injury extending into the prostatic urethra)
  • Type 5 (anterior tear of the bulbous urethra)
17
Q

What is the most common type of urethral injury?

A

Type 3 (tear of the membranous and bulbar urethra)

18
Q

What is the difference between a type 2 and a type 3 urethral injury?

A

Both involve the membranous urethra, but type 3 also tears the urogenital diaphragm and involves the bulbous urethra

19
Q

Which ureathra injury types are associated with incontinence?

A

Types 2, 3, and 4

20
Q

Urethral injury type with extraperitoneal contrast, but no perineal contrast on retrograde urethrogram?

A

Type 2 (tear of the membranous urethra)

21
Q

Urethral injury type with extraperitoneal and perineal contrast on retrograde urethrogram…

A

Type 3 (tear of the bulbous and membranous urethra)

22
Q

What is the site of male urethral injury during a straddle injury?

A

The bulbous urethra

Note: A straddle injury is when the urethra is smashed against the pubic symphysis, usually from the pts groin smashing against their bicycle crossbar.

23
Q

How can you differentiate a straddle injury from a gonococcal urethral stricture?

A

Straddle injuries produce short segment strictures of the proximal bulbous urethra

Gonococcal strictures are usually long segment strictures of the distal bulbar urethra

24
Q
A

Long segment, irregular, beaded narrowing of the distal bulbar urethra, suggestive of gonococcal urethral stricture

Note: The Cowper glands are also opacified.

25
Q

Why were pancreatic transplants often associated with urethral injury?

A

Pancreatic transplants used to drain to the bladder, and leakage from urethral injury occurred in ~5% of pts

26
Q

Retrograde urethrogram

A

Think condyloma acuminatum

Note: Multiple small filling defects. Instrumentation (including retrograde urethrogram) is not recommended due to the risk of retrograde seeding.

27
Q

Retrograde urethrogram

A

Urethrorectal fistula

Note: This is usually post radiation (especially brachytherapy).

28
Q

Retrograde urethrogram

A

Urethral diverticulum

Note: This is usually due to long term foley placement.

29
Q

What is the most common cancer of the male urethra?

A

Squamous cell carcinoma (80%)

Note: This is not true for the prostatic urethra, where 90% of cancers are transitional cell carcinoma.

30
Q

What is the most common cancer of the prostatic urethra?

A

Transitional cell carcinoma (90%)

Note: This is unlike the rest of the urethra, where squamous cell carcinoma is much more common (80%). Think of the prostatic urethra as being part of the bladder.

31
Q

What is the most common cancer of a male urethral diverticulum?

A

Adenocarcinoma (almost always)

Note: Non-diverticular urethral cancers (outside the prostatic urethra) are usually squamous cell carcinoma.

32
Q
A

Female urethral diverticulum

Note: Urethral diverticula are more common in females due to recurrent UTIs.

33
Q
A

Think urethral diverticulum

34
Q
A

Urethral diverticulum

Note: This is the “female prostate” sign.

35
Q

What is the most common cancer of a female urethral diverticulum?

A

Adenocarcinoma (60%)

36
Q

Bladder mass with calcifications…

A

Think squamous cell carcinoma (possibly in the setting of schistosomiasis infection)

37
Q

Adenocarcinoma is a rare collecting system/bladder cancer, except in…

A
  • Urachal remnants
  • Bladder exstrophy
  • Urethral diverticula