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Testis

The normal adult testis is ovoid in shape and measures approximately 3 to 5 cm in length by 2 to 3 cm in width

measure approximately 3-5 cm (length),  3 cm (AP) x 2-4 cm (TR) with a volume of 12.5-19 mL 2.

The size of the testicle varies with age, increasing in size from birth to puberty and then decreasing later in life.

Monster Hydroceles of a Newborn
Ashley Davidoff MD

Adult Male

Normal sized testes in a 30 year old male sagittal plane measuring 3.7 X 1.7 cms. It is ovoid in shape.
Ashley Davidoff MD 133348

133349.jpg

 Normal sized testes in a 30 year old male sagittal plane measuring 2.3 cms. It is more spheroidal in shape in this projection.
Ashley Davidoff MD 133349

Most adult testicles are about the same size.

US of both testes in the transverse plane showing the testes being about the same size
Ashley Davidoff MD
133340

It is common for one to be slightly bigger than the other and for or one testicle to hang lower than the other.

CT 3D Surface Rendering of the Testes and Penis
Ashley Davidoff MD
David’s Privates Magnified
Right Testis Slightly Larger than the Left
US in the sagittal and transverse planes of the right testes (a and c) and the left testis (b and d) reveal the right testes being only slightly larger than the left. The right measures 4.5 X 2.3 X 3.1 with a volume of 17 ccs, and the left measures 4.4 X 2 X 2.8cms with a volume of 13 ccs
Ashley Davidoff MD 1334022c
Normal Size with Slight Variation of Right vs Left
47 M normal teste
Ashley DAvidoff MD
1333510

133513.jpg

 Normal testes 45M CT scan
Note epididymis on the right which is isodense with the testes. Also in this Plane the left testis is slightly larger than the right.
Ashley DAvidoff MD
133513

 

Aging Testis

Atrophy
63 M Normal
but small testis
Ashley Davidoff MD
133528
US in the transverse plane through both testes in an 86-year-old male shows bilaterally small testes, likely due to age related atrophy. The right measures 2.7 X 1.4 X 1.4 cms, and the left measures 2.8 X 1.3 X 1.4 cms. These findings are likely related to age
Ashley Davidoff MD 133656c

 

Small Testis and Seminoma

62-year-old male presents for evaluation of hypogonadism

Ultrasound shows an abnormal right testis with a mass.

US in the transverse plane through both testes shows decrease echogenicity and diffuse heterogeneity of the smaller right testis, with foci of microlithiasis.
Ashley Davidoff MD 133711
US in the transverse plane through the right testis shows decrease echogenicity and diffuse heterogeneity of a small right testis, with foci of microlithiasis.
Ashley Davidoff MD 133714
US in the sagittal plane through the right testis shows a dominant mass measuring 1.5 X 1.4 cms.
Ashley Davidoff MD 133729
Doppler US in the sagittal plane through the right testis shows minimal vascularity in the dominant mass.
Ashley Davidoff MD 133727

Pathology revealed a stage 1 seminoma.

Large Testis and Acute Torsion
Doppler US in the transverse plane through both testes shows enlargement and no flow to the right testis consistent with the diagnosis of acute torsion.
Ashley Davidoff MD 133738
US in the sagittal and transverse planes through the right testis shows diffuse swelling with a total volume of 30 ccs.
Ashley Davidoff MD 133741
US in the transverse plane through the right spermatic cord is swollen.
Ashley Davidoff MD 133741

 

From the mediastinum testis, several radiating septa extend into the testis forming 250-400 lobules. Each of these lobules contains 2-3 seminiferous tubules. Seminiferous tubules carry the sperm via tubuli recti into a dilated space within the mediastinum testis which is known as the rete testis, which drains into the epididymis through 10-15 efferent ductules 1. Efferent ducts in the head of the epididymis (globus major) unite to form a single duct (globus minor) in the body and tail region, which continues as the ductus deferens (vas deferens).

The testes are supplied by testicular arteries, arising from the aorta, just below the origin of renal arteries.

The testes are drained by a plexus of veins (pampiniform plexus), which continue as the testicular veins. The right testicular vein directly drains into the inferior vena cava (IVC), while the left testicular vein drains into the left renal vein.

Lymphatic drainage of the testes is through lymphatics running with the testicular arteries, draining into para-aortic lymph nodes.

Testes receive autonomic (sympathetic) innervation from the spermatic plexus, originating from the para-aortic ganglia.

See also: Testicular and scrotal ultrasound

The normal testes have a homogenous, moderately echogenic pattern. A testicle is surrounded by a thin echogenic fibrous band, which represents the visceral component of the tunica vaginalis and the tunica albuginea. In the absence of intrascrotal fluid, the tunica is usually visualized only at its hilum as an echogenic structure, where it invaginates into the testis, to form the mediastinum testis.

Intratesticular arteries are low resistance vessels with a mean resistive index (RI) of 0.62 (0.48-0.75) 1.

  • T1: testes and epididymides have homogenously intermediate signal
  • T2: testes have hyperintense signal, with slightly lower signal in the epididymides

Tunica albuginea has hypointense signal on both T1 and T2 weighted images.

See: testicular descent

“Testicle” is thought to arise from the Latin word “testis” (witness, one who “testifies”). The connection between a witness and the term for a male sex organ is thought to be that the testicles are a sign of virility and under Roman law, no person was allowed to be a witness unless his testicles were present (i.e. neither eunuchs nor women were felt to be reliable witnesses!) 4.

Anatomy: Abdominopelvic

Anatomy: Abdominopelvic

Epiddiymis