skrotum

Skrotum, also known as the scrotum, is a pouch of skin and underlying tissue that houses the testes. It forms part of the external male genitalia and sits in the perineal region behind the penis. It protects the testes and helps regulate their temperature.

Anatomy: The scrotum comprises skin, a smooth muscle layer called the dartos, and an outer fibrous tunica. Inside lie the testes and epididymides, each covered by the tunica vaginalis. The spermatic cord, with the vas deferens, blood vessels, and nerves, passes through the inguinal canal. The scrotum is divided into two compartments by a septum, and the cremaster muscle surrounds the cord.

Function: The main role is thermoregulation for efficient spermatogenesis. The scrotum keeps the testes cooler than core body temperature by adjusting skin tension via the dartos and cremaster muscles and by changing position relative to the body.

Development: The scrotum develops from the labioscrotal swellings. Testicular descent into the scrotum occurs during fetal development, guided by the gubernaculum. Undescended testes (cryptorchidism) may affect fertility and cancer risk and sometimes require treatment.

Clinical notes: Common conditions include torsion of the spermatic cord (acute pain and swelling), hydrocele (fluid around the testis), varicocele (dilated veins), and epididymitis or orchitis (inflammation). Regular self-examination and medical evaluation for sudden or persistent swelling, pain, or lumps are advised.

Summary: The skrotum is an external structure that houses the testes and supports their function by maintaining appropriate temperature and protection. It comprises skin, the dartos and cremaster muscles, tunica vaginalis, and receives blood supply and innervation from surrounding vessels and nerves.