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Structure

Testis

Not medically reviewed · Content last updated · 2 min read ·

This is the date the draft was written, not a medical review date.

The testes are paired male gonads that produce spermatozoa and testosterone. They lie in the scrotum, which keeps them at a temperature slightly below core body temperature.

Terminologia Anatomica (Latin): Testis · Open in the 3D atlas

Location

Each testis lies in the scrotum, suspended by the spermatic cord, having descended from the posterior abdominal wall through the inguinal canal (usually before birth). It is enclosed by the tunica vaginalis (a peritoneal remnant) with the epididymis on its posterolateral surface.

Structure

A thick fibrous tunica albuginea encloses the testis and forms the mediastinum testis, dividing it into about 250 lobules (approximate) containing coiled seminiferous tubules lined with Sertoli and germ cells; Leydig cells lie in the interstitium. Tubules converge to the rete testis, efferent ductules and the epididymis, which continues as the ductus deferens.

Blood supply

The testicular artery arises from the abdominal aorta just below the renal arteries and travels in the spermatic cord, with contributions from the artery to the ductus deferens and the cremasteric artery. Venous drainage is by the pampiniform plexus, which forms the testicular vein: the right drains into the inferior vena cava and the left into the left renal vein. Lymph drains to the para-aortic (lumbar) nodes, not the inguinal nodes.

Innervation

The testicular plexus (sympathetic T10-T11, with afferent fibres) accompanies the testicular artery. The scrotal skin is supplied by the ilioinguinal, genitofemoral (genital branch) and pudendal nerves, and the cremaster by the genital branch of the genitofemoral nerve. Testicular pain is felt in the T10 region, whereas scrotal wall pain is localised.

Function

Spermatogenesis occurs in the seminiferous tubules under FSH and testosterone, while Leydig cells secrete testosterone under LH. The scrotum and the pampiniform plexus (countercurrent heat exchange) maintain the lower temperature needed for spermatogenesis.

Clinical correlations

Testicular torsion is a surgical emergency in adolescents; other conditions are cryptorchidism, hydrocele, varicocele (more often left, linked to the venous drainage into the renal vein), epididymo-orchitis and germ-cell tumours, which spread to the para-aortic nodes. A new right-sided varicocele or a rapidly forming one prompts a search for a retroperitoneal cause; management follows local guidelines.

Common exam points

  • Testicular artery from the aorta (about L2); left vein to left renal vein, right vein to IVC.
  • Lymph drains to para-aortic nodes; scrotal skin lymph drains to superficial inguinal nodes.
  • Pampiniform plexus cools arterial blood (countercurrent).
  • Spermatic cord layers derive from the abdominal wall (external and internal spermatic fasciae, cremasteric muscle).
  • Torsion: sudden severe pain, high-riding testis, absent cremasteric reflex.

References

  1. Drake RL, Vogl AW, Mitchell AWM. Gray's Anatomy for Students. Elsevier — Tier 3 (textbook)
  2. Moore KL, Dalley AF, Agur AMR. Clinically Oriented Anatomy. Wolters Kluwer, 8th edition (2018) — Tier 3 (textbook)
  3. Hall JE, Hall ME. Guyton and Hall Textbook of Medical Physiology. Elsevier, 14th edition (2020) — Tier 3 (textbook)

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