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Grayscale Evaluation and Measuring Parameters
Scrotal ultrasound is the primary imaging modality for evaluating scrotal structures, including the testes, epididymis, and spermatic cord. It provides detailed anatomical and pathological information using high-frequency linear transducers (7.5–15 MHz). Color Doppler and spectral Doppler imaging are also used to assess vascularity.Scrotal Structures
1.Testes
2. Epididymis
3. Spermatic cord
4. Tunica albuginea and tunica vaginalis
5. Scrotal wall
6. Vesels
1. Testes
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➤Echogenicity: Homogeneous, medium-level echotexture.
➤Size: Normal Adult Testicle Size
- Length: 35–50 cm
- Width: 20–40 cm
- Height: 20–30 cm
- Volume: 15–25 mL
General Reference Values:
Neonates: ~0.27 mL
Prepubertal Boys: ~1–3 mL
Puberty (10–14 years): ~4–12 mL
Adults: 12–25 mL [±2–5 mL]. (average: ~18–20 mL) The normal sonographic volume of the testes varies by age and individual, but for adult males, the typical testicular volume ranges from 12 to 25 mL per testis
Prepubertal Boys: ~1–3 mL
Puberty (10–14 years): ~4–12 mL
Adults: 12–25 mL [±2–5 mL]. (average: ~18–20 mL) The normal sonographic volume of the testes varies by age and individual, but for adult males, the typical testicular volume ranges from 12 to 25 mL per testis
Formula for Testicular Volume Calculation:
Testicular volume can be estimated using the ellipsoid formula:
Volume=0.52×Length×Width×Height (All measurements in cm, result in mL).
V=0.52 x 3.67cm x 2.62 cm x 2.32cm
V=0.52 x 22.30cm
V=11.60
Testicular volume = 11.6 mL/cc/gm. proved.
The medical term for an enlarged testicle is macroorchidism.
The medical term for a small testicle is Microorchidism/Testicular Atrophy
➤Orchidometer Average Testicle Size Comparison
An orchidometer is a medical instrument used to measure testicular volume, typically consisting of a series of ellipsoid beads ranging from 1 mL to 25 mL in size. It helps assess normal development, puberty stages, and detect abnormalities like hypogonadism or testicular atrophy.
➤Vascularity: Symmetric blood flow in intratesticular arteries (low-resistance pattern on spectral Doppler).
Below 4 mL in adults: Considered testicular atrophy/micro-orchidism.
Above 25 mL: Possible Enlarged testicle/macro-orchidism, seen in conditions
like Klinefelter syndrome.
2. Epididymis
_______________________
- Echogenicity: Iso- to hypoechoic compared to the testis
- Size:
- Head: 10–15 mm (largest part, superior to testis)
- Body: 2–4 mm
- Tail: 2–5 mm
- Vascularity: Mild blood flow seen with Doppler
3. Spermatic cord
➤Size: The normal thickness of the spermatic cord varies slightly but is generally within the following range:In children: ~4–8 mm.
Spermatic Cord Considered Thickened.
- >15 mm in adults
- >8 mm in children
The size may vary depending on factors like age, temperature, and physiological conditions. Enlargement or thickening of the spermatic cord can indicate conditions like varicocele, inguinal hernia, hydrocele, or spermatic cord lipoma. Funiculitis (Spermatic Cord Inflammation)/Spermatic Cord Edema.
➤Echogenicity: Hypoechoic, tubular structures
➤Doppler: Blood flow within spermatic arteries and veins
➤Doppler: Blood flow within spermatic arteries and veins
➤Contents: Vas deferens, arteries, veins, lymphatics, and nerves
The spermatic cord is a bundle of structures that pass through the inguinal canal to the testis. It contains the following structures:
A. Vas Deferens (Ductus Deferens)
- A muscular tube that transports sperm from the epididymis to the ejaculatory duct.
- Testicular artery (branch of the abdominal aorta) – supplies blood to the testes.
- Artery to the vas deferens (branch of the inferior vesical artery) – supplies the vas deferens.
- Cremasteric artery (branch of the inferior epigastric artery) – supplies the cremaster muscle.
- Pampiniform plexus – a network of veins that drains into the testicular vein (helps regulate testicular temperature).
- Genital branch of the genitofemoral nerve – innervates the cremaster muscle.
- Sympathetic nerve fibers – regulate blood flow.
- Ilioinguinal nerve (runs alongside but is not inside the spermatic cord) – provides sensation to the scrotum.
- Drain into the para-aortic lymph nodes.
- A serous membrane derived from the peritoneum.
- Derived from the internal oblique muscle, responsible for the cremasteric reflex (pulling the testes upward in response to cold or touch).
➤Tunica Albuginea: Thin, echogenic line surrounding the testis.
➤Tunica Vaginalis: No abnormal fluid accumulation.
➤Tunica Vaginalis: No abnormal fluid accumulation.
5. Scrotal wall
➤Thickness: <8 mm.
➤Echotexture: Uniform and hypoechoic.No abnormal fluid collections (e.g., hydrocele, hematocele).
