Scrotum

The seminiferous tubules converge to form

Tubuli recti

Scanning protocol for US scrotum

Generous amount of warm gel. High frequency probes, 10-14 MHz. Side by side comparison of testes. Each testis scanned from superior to inferior.

Largest part of the epididymis, located adjacent to superior pole of testis

Globus major

Tail of the epididymis (posterior)

Globus minor

Triangular shaped with rounded edges and echogenicity similar to that of the testis

Head of epididymis

Sonographic appearance of mediastinum testis

Highly echogenic. In longitudinal, appears as a line extending superior to inferior pole of the testis

Sperm is produced through a process called

Spermatogenesis

Ejaculatory duct empties into the

Urethra

Right testicular vein drains into

IVC

Spermatic cord extends from scrotum through inguinal canal and inguinal rings to the

Pelvis

At globus major (epididymal head) the efferent ductules converge to form this single convoluted duct

Ductus epididymis

The rete testes drain from the testes into the

Efferent ductules

The vas deferens is a continuation of the ductus epididymis connects to seminal vesicles to form

Ejaculatory ducts

Efferent ductules drain into tubules that form

Epididymal head

Composed of head, body, and tail

Epididymis

Small ovoid structure located beneath the head of the epididymis

Appendix epididymis

Only seen when there is fluid in the scrotal scan to outline it, appears as a small oval slightly more hypoechoic than testes

Appendix testis

Sonographic appearance of epididymis

Medium level echoes equal to or slightly more echogenic than normal testes

Sonographic appearance of testes

Medium level echoes, even texture similar to normal thyroid

Multiple septations arise from the tunica albuginea to form

Mediastinum testis (sonographically seen as an echogenic line extending superior to the inferior pole)

Branch of vesical artery (branch of internal iliac artery) supplies vas deferens and epididymis

Deferential artery

Amount of fluid found between the layers of the tunica vaginalis

1-2 ml

Branch of inferior epigastric artery (branch of external iliac artery) supplies the paratesticular tissue

Cremasteric artery

Muscle that surrounds each testicle and extends into the abdomen over the spermatic cord

Cremasteric muscle

Septum that divides scrotum internally into sacs. Septum contains superficial fascia and contractile tissue

Dartos or tunica dartos

Appearance of testes on US

Evaluate size, echogenicity, and structure of each testis. Parenchyma should be uniform with equal echogenicity between sides. Is there mass, cystic or solid? Is mass intratesticular or extratesticular? Is one testis larger than other? Swollen? Shrunken? Skin thickening? Doppler flow absence? Check epididymis flow.

Left testicular vein drains into

Left renal vein

US examination of testicles

Long: lateral, middle, and medial images. Trans: upper, middle, and lower images. Color Doppler and/or pulsed wave Doppler. Comparison of testicles. Separate image of epididymis.

Divides scrotum externally into two parts

Median raphe

Clinical patient questions regarding US scrotum

Palpable mass, pain, swelling? Describe symptoms to include history, location, and duration of pain. Trauma? Previous procedure, vasectomy?

Network of veins that drain the spermatic cord and epididymis

Pampiniform plexus

Function of cremasteric muscle

Regulates the temperature of the testicles

Tubuli recti enter the mediastinum testis forming a network of channels called

Rete testis

Pouch of skin that is continuous with the abdomen.

Scrotum

Septula form lobules (wedge shaped compartments) which contain

Seminiferous tubules (very tortuous)

Flow of seminal fluid

Seminiferous tubules, tubuli recti, rete testis, efferent ductules, ductus epididymis, globus major, globus minor, vas deferens

Vas deferens, testicular arteries, venous pampiniform plexus, lymphatics, autonomic nerves, and fiber of cremaster form

Spermatic cord (suspends testis in the scrotum)

Patient positioning for US scrotum

Supine position. Penis positioned on abdomen and covered with a towel. Rolled towel placed between thighs to support scrotum.

Paired male reproductive glands where spermatozoa are produced

Testes (oval and measure 5 x 3 x 3 cm)

Scrotal sac contents

Testicles, epididymis, vas deferens, blood vessels, spermatic cords, fluid

Arises from the aorta just below renal arteries, supplies testis

Testicular artery

Scrotal venous system divided into three veins

Testicular, deferential, and cremasteric veins

White fibrous tissue covering each testicle

Tunica albuginea

Membrane consisting of a visceral layer (adherent to the testis) and a parietal layer (adherent to the scrotum) lines the inner wall of scrotum

Tunica vaginalis

Junction of the ejaculatory duct and the urethra

Verumontanum