Testes !

The testes (testicles) are the two oval glands in the scrotum that make sperm and testosterone; they hang outside the body because sperm need a cooler place.

Official name: Testis

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What it is

Two oval glands, about 4-5 cm long, in the scrotum, each in a tough coat (tunica albuginea) inside a serous sac (tunica vaginalis). They form high in the abdomen and descend into the scrotum before birth.

What it does

Make sperm and testosterone; sperm production needs a temperature about 2-3 °C below body temperature, which is why they hang outside the body.

Key facts

Where: In the scrotum (left usually lower), each in a tunica albuginea inside the tunica vaginalis; formed on the posterior abdominal wall and descended through the inguinal canal before birth
Blood supply: Testicular artery (aorta, about L2); cremasteric and deferential arteries; veins by the pampiniform plexus to the IVC (right) and left renal vein (left)
Nerve: Testicular plexus along the artery (sympathetic, T10); pain referred to the umbilical region; cremasteric reflex (genitofemoral, L1–L2) often absent in torsion
Function: Sperm (seminiferous tubules, Sertoli cells) and testosterone (Leydig cells); lymph to para-aortic nodes near the renal vessels, not to the groin

Relations

Above: Spermatic cord, attached at the upper pole, with the head of the epididymis and the appendix testis
Behind: Epididymis along the posterolateral border and the mediastinum testis, where vessels and ducts enter and leave
Medial: Scrotal septum, separating it from the other testis
Superficial: Tunica vaginalis, internal spermatic fascia, cremaster, external spermatic fascia, dartos and scrotal skin

How to find it

Examined standing and lying: each testis is held between thumb and fingers and compared for size and consistency (smooth, firm, rubbery), with the epididymis felt behind it. In infants, the examiner checks that both are in the scrotum, sweeping down along the inguinal canal.

Examination

Cremasteric reflex: stroking the upper inner thigh lifts the testis on that side (L1–L2); usually absent in torsion
Transillumination: light passes through a hydrocele but not through a solid tumour or blood
Blue dot sign: a small blue-black spot at the upper pole seen through the skin suggests a twisted appendix testis rather than testicular torsion

On imaging

Scrotal ultrasound with colour Doppler comes first: torsion shows absent or reduced flow and a twisted cord ('whirlpool' sign); cancer shows a solid, usually dark (hypoechoic) mass inside the testis; microlithiasis appears as bright dots.

Common problems

Undescended testis (cryptorchidism): checked at birth; corrected in early childhood.
Testicular torsion: the testis twists on its cord; sudden severe pain, an emergency.
Testicular cancer, most common in young men (about 15-35 years); usually a painless lump.
Hydrocele (fluid around the testis).

How it is diagnosed

Examination and self-examination; scrotal ultrasound; tumour markers in the blood when cancer is suspected.

Treatment

Emergency surgery to untwist and fix a torsion, ideally within about 6 hours.
Surgery to bring down an undescended testis (orchidopexy).
Removal of the testis through the groin (radical orchiectomy) for cancer, often followed by other treatment.

Clinical notes

Hydrocele: fluid in the tunica vaginalis surrounds the testis, which can then be hard to feel; in infants a communicating hydrocele shares the open processus vaginalis of an indirect hernia
Testicular cancer is mostly germ cell tumours (seminoma and non-seminoma) in young men; alpha-fetoprotein, beta-hCG and LDH are the tumour markers

Anatomical variants

Appendix testis: a remnant of the paramesonephric duct at the upper pole; it can twist and mimic torsion
Ectopic testis lies off the normal path of descent (perineum, thigh, above the pubis); an undescended testis stops along the path; a retractile testis can be brought down and stays

Development

Forms on the posterior abdominal wall near the kidneys, which is why its artery comes from the aorta and its lymph goes to para-aortic nodes. The gubernaculum guides it through the inguinal canal, usually into the scrotum in the last months of pregnancy, with the processus vaginalis in front.

Test yourself

Think of the answer, then tap the question to see it.

What are the classic findings of testicular torsion?

Sudden severe pain, a high-riding testis lying horizontally and an absent cremasteric reflex; salvage is best within about 6 hours.

What anatomical variant predisposes to testicular torsion?

The bell-clapper deformity: the tunica vaginalis attaches too high, so the testis hangs free.

Why is suspected testicular cancer removed through the groin rather than the scrotum?

To avoid opening a second lymph pathway to the groin nodes; testicular lymph normally drains to para-aortic nodes.

What does the blue dot sign suggest?

A twisted appendix testis rather than torsion of the testis.

Which tumour markers are used in testicular germ cell tumours?

Alpha-fetoprotein, beta-hCG and LDH.

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Educational information, not medical advice. For any symptom, see a health professional.

Its names

Official Latin (TA2): testis
Official Spanish (DeCS): Testículo
English (TA2): Testis
Also called: testicle

Sources: Anatomy, Abdomen and Pelvis: Testes.

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Representative model, for educational purposes only.

Testes highlighted on the Durgical 3D model