Chapter 23 – Scrotum: Anatomy, Sonography & Pathology

A comprehensive set of question-and-answer flashcards covering the anatomy, vascular supply, scanning techniques, and common scrotal pathologies described in Chapter 23.

What are the typical adult testis measurements (length × width × height)?

Approximately 3–5 cm long, 2–4 cm wide, and 3 cm high.

Into what structures are the seminiferous tubules organized within each testis?

They are grouped into lobules that converge to form the rete testis in the mediastinum.

Through which ducts does the rete testis drain into the epididymis?

Via the efferent ductules that enter the head of the epididymis.

What is the total length of the epididymis and its three anatomical parts?

About 6–7 cm long; divided into head, body, and tail.

Which part of the epididymis is the largest and what is its typical width?

The head; it measures roughly 6–15 mm in width.

Compared with the testis, how does the normal epididymis appear on ultrasound?

It is generally isoechoic but with a slightly coarser echo-texture.

What single duct forms from converging efferent ductules in the epididymis body and tail?

The ductus (vas) epididymis, which becomes the vas deferens.

What embryologic remnant at the superior testicular pole can tors and calcify into a 'scrotal pearl'?

The testicular appendix (appendix testis).

Which dense fibrous layer covers each testis and forms the mediastinum?

The tunica albuginea.

How does the mediastinum of the testis appear sonographically?

As a bright, linear, hyperechoic band coursing through the testis.

Name the two layers of the tunica vaginalis and the space where hydroceles form.

Parietal (lining scrotal wall) and visceral (covering testis/epididymis); fluid collects in the space between these layers.

Which ligament anchors the inferior pole of the testis and helps prevent torsion?

The scrotal ligament.

What muscle raises and lowers the testis to regulate temperature?

The cremaster muscle.

With which structure does the vas deferens unite to create the ejaculatory duct?

The duct of the seminal vesicle.

Where is the verumontanum located?

At the junction of the ejaculatory ducts with the urethra.

List the main contents of the spermatic cord.

Vas deferens, testicular artery, pampiniform plexus veins, lymphatics, nerves, and cremaster muscle fibers.

Trace the main arterial branching inside the testis from largest to smallest.

Testicular artery → capsular arteries → centripetal arteries → recurrent rami (centrifugal branches).

Into which veins do the right and left testicular veins drain?

Right drains into the IVC; left drains into the left renal vein.

Which transducer frequency range is recommended for scrotal sonography?

High-frequency probes, typically 10–14 MHz.

Name four key sonographic parameters routinely compared between testes during a scan.

Size, echogenicity, internal structure, and blood-flow patterns (using color/power Doppler).

List five sonographic signs of testicular rupture.

Focal tissue alteration, interruption of tunica albuginea, irregular contour, scrotal wall thickening, hematocele and disrupted blood flow across the surface.

Within what time frame must surgery occur for >90 % salvage of a ruptured testis?

Within 72 hours after injury.

What sonographic appearance characterizes an acute hematocele?

Complex fluid with low-level echoes that may swirl; over time, fluid-fluid levels or septations develop.

How does acute epididymitis typically appear on color Doppler?

Enlarged, hypoechoic epididymis with marked hyperemic (increased) blood flow.

When infection extends from the epididymis into the testis it is called .

Epididymo-orchitis.

State two associated findings that may accompany epididymo-orchitis.

Scrotal skin thickening and hydrocele or pyocele formation.

Why can severe orchitis lead to testicular infarction?

Swelling inside the rigid tunica albuginea can compress vessels, obstructing blood flow and causing ischemia.

What congenital anomaly predisposes to torsion and what is its mechanism?

Bell-clapper deformity; the testis lacks fixation at the bare area, allowing free rotation within the scrotum.

Within how many hours of torsion onset is salvage most successful?

5–6 hours (80–100 % salvage); after 12 hours, only ~20 % are saved.

At what age does testicular torsion peak?

Around 14 years of age.

Define spermatocele and its typical location.

A cystic dilation of efferent ductules, always located in the epididymal head containing proteinaceous fluid and sperm.

Differentiate an epididymal cyst from a spermatocele.

Epididymal cysts are simple, clear, smaller fluid collections anywhere in the epididymis; spermatoceles are in the head and may contain echoes/sperm.

What is a tunica albuginea cyst’s effect on the testis?

It may protrude from the tunica and distort the testicular contour.

Define varicocele and state its usual side and diameter criterion.

Dilated pampiniform plexus veins (> 2 mm); more common on the left.

Which maneuver or position accentuates varicoceles on ultrasound?

Valsalva maneuver or standing upright increases venous diameter and flow reversal.

What structure is most commonly seen in a scrotal hernia?

Bowel (demonstrating peristalsis on real-time imaging).

What is the most common cause of painless scrotal swelling?

Hydrocele (serous fluid collection between tunica vaginalis layers).

Differentiate pyocele from hematocele.

Pyocele contains pus (infection); hematocele contains blood (trauma, surgery, tumors, or torsion).

What condition appears as a painful, vascular solid mass in the epididymis of vasectomy patients?

Sperm granuloma (inflammatory reaction to leaked sperm).

Tubular ectasia of the rete testis is associated with what other finding?

An ipsilateral epididymal cyst or obstruction.

How do intratesticular simple cysts usually present and in whom are they most common?

Near the mediastinum, single or multiple, in men over 40; often coexist with spermatoceles.

Describe testicular microlithiasis and its clinical significance.

Multiple bilateral micro-calcifications <3 mm that are non-shadowing; associated (but not causal) with increased risk of malignancy.

What percentage of all male cancers is testicular cancer and which age group is most affected?

~1 % of male cancers; most common in men 15–35 years old.

Why are intra-testicular masses more concerning than extra-testicular masses?

Intra-testicular masses are more likely malignant, whereas extra-testicular masses are usually benign.

Which tumor markers are elevated in most germ cell tumors?

Alpha-fetoprotein (AFP) and human chorionic gonadotropin (hCG).

What is the most common type of germ cell tumor and its classic ultrasound appearance?

Seminoma; homogenous, hypoechoic mass with smooth borders.

From which primary sites do testicular metastases most frequently arise?

Prostate and kidney cancers; metastasis is usually bilateral with multiple lesions.

How do testicular lymphoma or leukemia typically appear sonographically?

Enlarged testes that are diffusely hypoechoic or contain focal hypoechoic areas.

Where are undescended testes usually located, and what is their sonographic appearance?

Most often in the inguinal canal; smaller, less echogenic, homogeneous, and lacking a visible mediastinum.

How does cryptorchidism affect cancer risk?

Undescended testes carry up to an 8-fold increased risk of developing testicular cancer.