Ch 5b (normal scrotum) Flashcards
Where do the testes develop?
B/w posterior abdominal wall + peritoneum
When do the testes pass through the inguinal ring + lie in the scrotum?
7th month: inguinal ring
8th month: in scrotum
What is the gubernaculum testis?
The caudal genital ligament is continuous with a band of mesenchyme which connects the fetal testis to the developing scrotum
(seen during testicular descent in inguinal region)
When is the gubernaculum present?
Only during development of urinary + reproductive organs
What does the gubernaculum attach to?
Caudal end of testis
What does the gubernaculum do?
Anchors fetal testis to inguinal region to prevent upward movement
What is the name of the remnant that forms once the gubernaculum testis shrinks/disappears?
Scrotal ligament
Location of scrotal lig?
-Extends from inferior pole of testis
+
-From tail of epididymis to skin of scrotal wall
What does the scrotal lig do?
Secures the testis by keeping it in place + limiting the amount it can move around within the scrotum
What forms the tunica vaginalis?
When the testes descend into the scrotum, the peritoneal lining called the processus vaginalis fuses around the testis to form the tunica vaginalis
When does the communication b/w the tunica vaginalis + peritoneal cavity obliterate?
After birth
What 2 layers compose the tunica vaginalis?
Peritoneal sac with a visceral + parietal layer
What structures does the tunica vaginalis surround?
Covers + surrounds majority of testis + epididymis
What structures does the visceral + parietal layers of tunica vaginalis cover?
Visceral: testis + epididymis
Parietal: inner lining of scrotal wall
What are the visceral + parietal layers of the tunica vaginalis separated by?
A potential space that normally has some fluid in it
Is a small amount of fluid seen within the scrotum normal?
Yes
What is the tunica albuginea?
Fibrous sheath that covers the testis
SF of the tunica albuginea?
Thin echogenic line
What is the scrotum?
Fibromuscular sac that holds the testis
(it is composed of several layers of fascia + muscle)
What are the 6 layers of the scrotum?
-tunica dartos
-external spermatic fascia
-middle spermatic fascia
-cremasteric muscle
-internal spermatic fascia
-tunica vaginalis
Normal scrotal wall thickness?
2-8 mm
(depends on the state of contraction of the cremasteric muscle)
SF of normal scrotum?
-homogeneous
-slightly echogenic when compared to testis
The scrotum is divided into 2 parts by what structure?
Median raphe (midline septum)
What is the median raphe?
Fibrous band of tissue
-Runs ventral to under surface of penis
-Runs dorsal along middle of perineum to anus
3 major structures contained in the scrotum?
-spermatic cord
-epididymis (head, body, tail)
-testes
What do the testes look like + where are they?
Bilateral, symmetrical, ovoid glands in the scrotum
Normal testicle measurements?
3-5 cm x 2-3 cm x 2-3 cm
How much does each adult testicle weigh?
B/w 10-19 grams
Do the testes ever change in size?
Yes they change with age
(increases in size up to puberty then decreases later in life)
SF of testicles in adults?
-homogenous
-medium level echos (similar to thyroid gland)
-smooth contour
SF of testicles in children?
Hypoechoic + small
Testis are surrounded by a fibrous capsule called what?
Tunica albuginea
The tunica albuginea is covered by what?
Tunica vaginalis
What are the 2 layers of the tunica vaginalis that are separated by small amount of fluid?
-Parietal (outer)
-Visceral (inner)
What is the mediastinum testis?
It is an incomplete septum due to the tunica albuginea projecting posteriorly into the testis
The testicular parenchyma is made up of what?
Numerous seminiferous tubules
(which goes towards the mediastinum testis, opens into the rete testis, then drains into epi head)
What are rete testis?
Anastomosing network of delicate tubules located in the mediastium testis
SF of mediastinum testis?
Hyperechoic + linear
(image on slide looks like hyperechoic line going through the middle of the testis)
Are the small tubules of the rete testis normally seen?
No, unless they are dilated (aka tubular ectasia)
What is the path of the spermatic cords?
Pass from abdominal cavity through inguinal canal + down into the scrotum
Location of each spermatic cord?
Lies above/parallel to inguinal ligament
Function of the spermatic cord?
To suspend the testis in the scrotum
What is the spermatic cord composed of?
-Arteries (testicular, cremasteric + deferential)
-Veins of the pampiniform plexus
-Nerves
-Lymphatics
-Vas deferens
-Connective tissue
SF of spermatic cord in SAG + TRV?
SAG:
-Numerous hypoechoic, slightly tortuous, linear structures
-Measures up to 2mm
TRV:
-Numerous hypoechoic ovoid structures with echogenic borders (representing vascular walls + connective tissue)
Path of the vas deferens?
Runs in the spermatic cord, through the scrotum, inguinal canal + into the abdomen
Are the vas deferens a continuation of the epi?
Yes!
What are the vas deferens?
Thick paired muscular ducts
(transports sperm to urethra before ejaculation - think of them as the “sperm ducts”)
How long are the vas deferens?
About 45 cm in length
SF of vas deferens?
SAG: Linear hypoechoic structure superior to epi
TRV: ovoid structure (target / doughnut look)
Measurement of vas deferens in TRV?
Less than 0.5mm
Does a normal spermatic cord show blood flow within the arteries + veins of the pampiniform plexus at rest?
Minimal flow seen
Normal veins of pampiniform plexus measure what?
Less than 2mm
What does a valsalva look like on a normal pt?
Slightly increases venous flow
Should we do a valsalva on every scrotal exam?
Yes!
Measurement for a varicocele?
3mm or larger
Why are valsalva’s performed?
To check for dilation of scrotal veins
(use dual screen + CD for it)
Function of epididymis?
Stores small quantities of sperm prior to ejaculation
3 parts of epi?
-Head (globus major)
-Body (corpus)
-Tail (globus minor)
Location of epi head, body + tail?
Head: superolaterally to testis
Body: adjacent to posterolateral part of testis
Tail: inferolateral surface of testis + continues to become vas deferens
Which part of epi continues to become vas deferens?
Epi tail
SF of epi head?
-Homogeneous
-Isoechoic/slightly more echogenic than testis
-Triangular/tear drop shaped
-Located superior to testis
SF of epi body/tail?
-Isoechoic to hypoechoic compared to testis
-Narrow body + curved tail
-Smaller + more variable in position than head
-Usually located posterior + inferior to testis
-Best seen in SAG
What is an appendix testis?
-Ovoid or elongated protuberance
-5 mm in length
-Attached to upper pole testis
What is an appendix epididymis?
Approx. same size as the appendix testis (5mm)
What is the echogenicity of appendages of the testis + epi?
Isoechoic - echogenic
(found superior to testis + epi)
Appendix testis + epi’s are what type of remnant?
Embryologic remnants
Should we document an appendix testis or epi?
Yes always, they are not always seen on u/s
What is a vasectomy?
When the vas deferens get cut+ sealed in order to stop sperm from getting into the semen
Do we ask all pt’s if they have had a vasectomy for a scrotal exam?
Yes!
Types of changes to the epi after a vasectomy?
-enlargement of epi
-heterogeneous epi
-spermatoceles
-dilation of rete testis
-sperm granulomas
(40% of pt’s experience changes after procedure)
What 3 arteries supply scrotal blood flow?
Bilateral testicular, cremasteric + deferential arteries
Which artery provides major blood supply to testis?
Testicular arteries
What does the deferential artery supply?
Epi + vas deferens
What does the cremasteric artery supply?
Peritesticular tissues
Where do testicular arteries arise from?
From anterior aspect of aorta, below the renal arteries, which then enter the spermatic cord at the internal inguinal ring with the other cord structures
The venous drainage from the scrotum travels through what structure?
Pampiniform plexus - then empties into the testicular veins
Right testicular vein drains into what?
IVC
Left testicular vein drains into what?
Left renal vein
(think left for left)
Would we be more worried for right or left side testicular dilatation?
Right side - it is more serious as it goes into the IVC
Do the testis have high or low vascular resistance?
Low - it is always receiving + wanting blood
What does low resistance mean?
When an organ wants blood (is not resisting flow) because it is vital for human existence
What does high resistance mean?
When an organ resists blood flow because its function is not essential for human existence (like muscles)
Does the testicular, intratesticular + epi arteries have high or low resistance?
Low resistance + high blood flow
Does the cremasteric + deferential arteries have high or low resistance?
High resistance + low blood flow
What is the primary function of the testes?
Production of sperm + testosterone
What is spermatogenesis?
Development of sperm cells
Where does spermatogenesis occur?
In seminiferous tubules
What cells secrete testosterone?
Cells of Leydig
What does testosterone do?
-Stimulates production of sperm
-Primary sex hormone responsible for development of male reproductive tissues + maintenance of male secondary sex characteristics
Where does sperm production occur in the testes?
Coiled structures called the seminiferous tubules
The epi is on the top or bottom of each testicle?
Top
A cord like structure where sperm mature + are stored is called the?
Epididymis
How does the sperm travel from the epi to the vas deferens?
It moves forward with smooth muscle contractions
The sperm arrives first where?
At the ampulla just above the prostate gland
(secretions from the seminal vesicle beside the ampulla then get added)
The seminal fluid gets propelled forward through which ducts towards the urethra?
The ejaculatory ducts
As the seminal fluid passes the prostate gland, what gets added to make semen?
A milky fluid
The semen gets ejaculated from the penis through which structure?
Urethra
What is the gold standard for evaluating pt’s with scrotal issues?
High frequency grayscale sonography with spectral, color + power doppler
Which transducer is best for scrotal exam?
12-18 MHz linear probe
(with spectral, color + power doppler capabilities)
Could we use a curvilinear probe?
Yes, for an increase FOV
What surgical history should we ask our pt?
-Vasectomy
-Hernia repair
-Orchiopexy (moves an undescended testis into the scrotum)
-Hydrocelectomy (surgery to remove hydrocele)
Should we ask our pt if they are currently being treated by antibiotics?
Yes, get them to locate the area of pain, swelling or palpable mass too
What are we comparing b/w both testicles during an exam?
Compare size, echogenicity + vascularity
CD is used to evaluate what in the testis?
Intratesticular arteries
Spectral doppler is used to document what?
The intratesticular arterial + venous waveforms
Are veins easy to see with CD?
No, hard to see
If no blood flow within the testis, what might this indicate?
Testicular torsion
Should we include the epi in SAG when imaging the middle + lower parts of testis?
Include the body/tail
Which plane is the spermatic cord, epi + skin thickness evaluated in?
Both SAG + TRV
