Anatomy of Abdomen: Testes and Epididymis

Anatomy of the Abdomen: Testes and Epididymis

Testes

• Are paired ovoid reproductive glands that produce sperms (spermatozoa) and the testosterone hormone
• Suspended in the scrotum by the spermatic cords, with the left testis usually suspended more inferiorly than the right testis
• Have a tough fibrous outer surface called the tunica albuginea
• Interior structure:
  • Tunica albuginea thickens into a ridge on its internal, posterior aspect as the mediastinum testis
  • Fibrous septa extend inward from the mediastinum, dividing the testis into 250 lobules
  • Each lobule contains 2-3 seminiferous tubules, which become straight tubules posteriorly and anastomose to form the rete testis
  • From the rete testis, about 12-14 efferent ductules arise and pierce the tunica albuginea, passing into the head of the epididymis

Epididymis

• Receiving ducts from the testis, with 12-14 efferent ductules
• Located above the testis, with a small appendage called the appendix epididymis, which is a remnant of the mesonephric duct
• May undergo torsion, causing acute pain

Appendix Testis and Appendix Epididymis

• Small appendages on the upper pole of the testis and epididymis, respectively
• Remnants of the paramesonephric (Müllerian) and mesonephric ducts, respectively
• May undergo torsion, causing acute pain

Tunica Vaginalis

• A double-layered peritoneal serous sac that invaginates the testis and epididymis anteriorly
• Composed of parietal and visceral layers, with a cavity in between
• The visceral layer is closely applied to the testis and epididymis, while the parietal layer lines the internal spermatic fascia
• The cavity contains a small amount of fluid, enabling the testis to move freely in the scrotum
• Sinus of the epididymis: a slit-like recess in the cavity of the tunica vaginalis, lying between the body of the epididymis and the posterolateral surface of the testis

Arterial Supply, Venous Drainage, and Lymphatic Drainage

• Not mentioned in detail in the provided text, but important for understanding the anatomy of the testes and epididymis

Clinical Relevance

• Hydrocele of the testes/hydrocele of the spermatic cord: a fluid-filled sac around the testis
• Hematocele of the testes: a collection of blood in the tunica vaginalis
• Torsion of the spermatic cord: a twisting of the spermatic cord, causing acute pain
• Varicocele: an abnormal enlargement of the pampiniform venous plexus in the scrotum, which may be noticed as soft lumps above the testicle and can be palpated like a bag of worms
• Malignant disease from the testis may spread to the lymph nodes at the root of the neck