Scrotum/penis/prostate

Superficial structures

Anatomy of the penis

root

body - corpora cavernosa x2 and corpus spongiosum x1

glans penis

Buck’s fascia

Arterial flow to the penis

internal iliac arteries → internal pudendal arteries → dorsal artery → cavernous artery → bulbourethral artery

Venous flow from the penis

superficial dorsal vein (prominent and visible) → deep dorsal vein → pudendal venous plexus → internal pudendal vein

Function of the penis

eject semen

sono appearance of the corpora cavernosa

paired

symmetrically round or oval

homogeneous

medium-level echoes

sono appearance of corpus spongiosum

homogeneous

medium-level echoes

Sono appearance Tunica albuginea (septum penis)

echogenic

Peyronie’s disease

calcified or fibrous tissue deposited in the dorsal penis

can cause the penis to bend

becomes painful when erect

extent defined by ultrasound

Penis stricture

urethra becomes narrowed

develops due to trauma or infection

seen when the urethra is distended with fluid

Impotence

inability to achieve or maintain an erection

Causes of impotence

poor arterial flow

multiple medications

venous leak

Impotence velocites

cavernosal peak systolic arterial > 30 cm/sec is normal

< 25 cm is poor arterial flow

Where does the prostate sit?

lies between the urogenital diaphragm and bladder outlet

inferior to the seminal vesicles

surrounds the prosthetic urethra

anterior to the rectum

posterior to space of retzius

Prostate shape

oval, cone, or chestnut shaped

3-4 cm in length

2-3 cm height and width

The prostate volume usually:

increases with age (<30 cc)

5 prostate lobes

anterior (fibromuscular portion)

middle

posterior

lateral (2)

Central zone

base of the prostate

25% glandular tissue

Peripheral zone

70% glandular tissue

extends from the base to the apex in the posterior gland

Transitional zone

5% glandular tissue

enlarges with BPH

Anterior fibromuscular stroma

devoid of glandular tissue

composed of only fibrous and muscular tissue

Prostate function

secretes a thin, alkaline fluid into the prostatic urethra by the prostatic ducts

constitutes the majority of the seminal fluid and aids in the motility of sperm

glandular tissue produces prostate specific antigen (PSA)

testosterone and dihydrotestosterone regulates prostate growth and function

MOST ACCURATE method to calculate prostate function

calculate prostate specific antigen density (PSAD)

Normal PSA value

< 4.0 mg/ml

Variants of the prostate

agenesis of the seminal vesicle

prostatic utricle cyst

ejaculatory duct cyst

mullerian duct cyst

agenesis of the vas deferens

MOST COMMON reason for a prostate exam

urinary symptoms

Eiffel tower appearance

verumontanum

Verumontanum

area where the seminal vesicles and ductus deferens empty into the urethra

Benign prostatic hypertrophy or hyperplasia (BPH)

frequently enlarged median lobe (transitional zone) bulging up towards the bladder

MOST COMMONLY seen in males over 70 years old

Symptoms of BPH

urinary hesistency

weak urine stream

dribbling

urinary frequency due to incomplete emptying

nocturia

hematuria

UTIs

Prostatitis

chronic inflammation of the prostate

may have moderate swelling

Sono findings of prostatitis

inhomogeneous texture with focal hypoechoic areas

commonly caliculi are present

capsular thickening and/or irregularity

Prostatic calculi

small (2-3 mm)

in BPH, typically arranged in a chain near the nodule

COMMON

Prostatic cysts are:

uncommon

Prostatic carcinomas are generally:

smaller and less echogenic than surrounding tissue

the larger it is the more isoechoic it becomes to surrounding tissue and eventually more echogenic

_______ of carcinomas may not be seen sonographically with the endorectal probe

25%

Anatomy of the scrotum

spermatic cord (bilateral)

vas deferens or seminal duct

epididymis

testes

Tunica albuginea

dense fibrous tissue surrounding the testes

forms the mediastinum testis

Tunica vaginalis

lines the inner wall of the scrotum

parietal and visceral layers

Where do hydroceles occur?

between the parietal and visceral layer of the tunica vaginalis

Epididymis in relation to the testicle

head starts more superior

body more lateral

tail is posterior

Spermatic cord

supporting structure of the testes (attaches posteriorly)

joins the seminal vesicle duct to form the ejaculatory ducts

Vas deferens/seminal duct

muscular cord designed to pump sperm from the epididymis into the prostatic segment of the urethra

ascends along the posterior border of the testis

stores sperm for up to several months

seminal vesicles produces fluid rich in fructose

Epididymis

stores sperm that is produced in the testicles

Testicles

bilateral ovoid glands located in the scrotum

homogeneous texture

responsible for the production of sperm and secretion of testosterone

Testicle size

3-4 cm in length

3 cm in AP

2-3 cm in width

Mediastinum testis

formed by the tunica albuginea

functions as a supporting system for arteries, veins, and lymphatics

echogenic line within the testes

Rete teste

anastomosis of tubules/lobules at the mediastinum testes

Appendix teste

hyatid of Morgagni

superior aspect of the testicle beneath the epididymal head

isoechoic to the testicle

remanent of the Mullerian duct

Retractile teste

testicles move freely from the scrotal sac back into the inguinal canal

Venous drainage from testes

right - drains directly into IVC

left - drains into the left renal vein

Indications for a scrotal ultrasound

pain

enlargement

palpable mass

undescended testes

f/u from orchiectomy

trauma

infertility

Median raphe

fibrous band of tissue that divides the scrotal sac into two pouches

Cryptoorchidism

aka undescended testes

may be found in the abdomen, inguinal canal, or ectopic location

MORE COMMON on the right side

MOST COMMON ectopic location for a testes

superficial inguinal pouch

Testicular ectopia

ectopic testicle cannot be manipulated into the correct place

Anorchia is MORE COMMON on the

left

Causes of anorchia

intrauterine testicular torsion or other forms of decreased vascular supply in utero

Polyorchidism is MORE COMMON

on the left (75%)

Increased incidence with polyorchidism

malignancy, cryptoorchidism, inguinal hernia, torsion

MOST COMMON inflammatory process in the scrotum

epididymitis

MOST COMMON cause of acute scrotal pain in adults

epididymitis

MOST COMMON CAUSE of scrotal torsion

bell-clapper deformity

MOST COMMON location for a spermatocele

head of the epididymis

MOST COMMON CAUSE of infertility in men

varicocele

more common to see on left side

MOST COMMON fluid collection in the scrotum

hydrocele

MOST COMMON extratesticular tumor

adenomatoid tumor

Sperm granuloma is MORE FREQUENTLY seen:

after a vasectomy

Onion skin sign

epidermoid cyst

MOST COMMON in men over 40

MOST COMMONLY CAUSED by untreated epididymo-orchitis

abscess

MOST COMMON malignant neoplasm to arise from an undescended teste

seminoma

Second most common carcinoma

embryonal cell carcinoma

occurs in men between the ages of 25-35

Teratomas are MORE COMMON in

infants and children

SECOND MOST COMMON tumor after a seminoma

mixed germ cell tumors

MOST COMMONLY occurs in men over 60 years old

lymphoma and leukemia

Primary site of metastases to the scrotum

prostate and kidney