Male Pelvis (Lecture 24)

What is the vas deferens?

Communication b/w the epididymis and ejaculatory ducts

How do the vas deferens travel?

Thru inguinal canal, cross superiorly to bladder, travel medially and inferiorly to unite w/ seminal vesicles to form ejaculatory duct

What is the ejaculatory duct? How does it travel?

- Union of the vas deferens and seminal vesicle duct

- Travels thru prostate to enter urethra at verumontanum

Where do the seminal vesicles lie in relation to the bladder and prostate?

SV are:

- Posterior to bladder

- Superior to prostate

What structure contributes to most of the semen volume?

Seminal vesicles

Where is the prostate? What is its function?

- Surrounds prostatic urethra, inferior to seminal vesicles

- Produces a weak acid that accounts for 20-30% of semen volume

What zones of the prostate make up the outer gland?

- Peripheral

- Central

What zones of the prostate make up the inner gland?

- Transition

- Periurethral glandular area

- Anterior fibromuscular stroma

TRUE or FALSE: The superior aspect of the prostate is referred to as the apex.

FALSE:

- Sup. prostate = base

- Inf. prostate = apex

What is the largest zone of the prostate?

Peripheral zone (accounts for 70% of glandular tissue)

What is the m/c site of prostate cancer?

Peripheral zone

What separates the peripheral zone of the prostate from the central and transition zones?

Surgical capsule

Where is the central zone of the prostate located?

Midline b/w peripheral and transition zone (contains 25% glandular tissue)

What zone of the prostate does the ejaculatory duct enter?

Central zone

TRUE or FALSE: The central zone is m/c site of BPH.

FALSE: The TRANSITION zone is m/c site of BPH. The central zone is relatively resistant to disease processes.

Where is the transition zone of the prostate?

- Completely surrounds urethra w/ verumontanum as its inferior border

(contains 5% glandular tissue)

TRUE or FALSE: Fibromuscular stroma make up most of the glandular tissue of the prostate.

FALSE: The fibromuscular stroma contains no glandular tissue> This makes it so little pathology occurs here

Where are periurethral glands located?

Embedded in smooth muscle of proximal urethra

What is the procedure for an endorectal U/S (include pt prep and procedure)?

1. Bowel is cleared the night before exam using an enema

2. Bladder is emptied

3. Pt lies LLD w/ knees bent

4. Pt is given a local anesthetic (lidocaine)

5. Pt is asked to take a deep breath and endorectal probe is inserted into rectum

What are normal SF of the prostate gland?

- Ovoid shape (in both trans and long)

- Homogenous (cannot differentiate b/w zones)

What are the transverse images take in a transrectal U/S exam? (HINT: 4)

Images start from superior --> inferior:

1. Seminal vesicles (most superior image)

2. Base of prostate

3. Mid prostate gland

4. Apex of prostate (most inferior image)

How do normal seminal vesicles appear sonographically?

- Hypoechoic

- Symmetrical

- Superolateral to prostate

- Bowtie appearance with transabdominal U/S

TRUE or FALSE: The periurethral area appears hypoechoic.

TRUE

TRUE or FALSE: The anterior fibromuscular stroma appears hypoechoic.

FALSE: The anterior fibromuscular stroma appears HYPERechoic.

What sagittal images are taken in a TRUS?

1. Midsagittal beak image: seminal vesicles entering prostate

2. Lateral/parasagittal: angle to rt and lt

What is a normal weight for the prostate gland?

- Younger pts = less than or equal to 20 grams (+/- 6g)

- Older men = less than or equal to 40g

What is a normal AP for the seminal vesicles?

1 cm

What is the approx dimensions of the prostate gland?

L x W x AP = 3cm x 4cm x 3cm

What is corpora amylacea? How does it appear sonographically?

- Proteinaceous material/calcifications commonly seen in the prostate

- SF: Eiffel tower appearance of calcifications along prostatic urethra in trans

What is the arterial supply of the prostate?

Internal iliac artery --> prostaticovesical artery --> prostatic artery + inferior vesical artery

What is the venous drainage of the prostate?

Prostatic venous plexus

TRUE or FALSE: Flow should be seen within a normal prostate gland.

TRUE: A prostate gland will show flow within the gland and at the capsule