Human Anatomy Part 1 - K. A. Dyubenko, A. K. Kolomiysev, Yu. B. Chaykovsky 2002

Special Part
Reproductive Systems, systemata genitalia — Male Reproductive System, systema masculinum
External Male Genitalia, organa genitalia masculina externa — Scrotum — Descent of the Testis into the Scrotum

The Testis originates from the primary Kidney (mesonephros) within the IV-V lumbar segments of the retroperitoneal space, where it remains for the first three months. By the 4th month of intrauterine development, the testis begins its caudal descent. As the fetus grows, the testis enlarges and displaces the parietal Peritoneum, resulting in The formation of two folds: one extending cranially toward the Diaphragm, known as the diaphragmatic ligament of the mesonephros, and the second extending caudally, known as the inguinal ligament of the mesonephros. Following the degeneration of the mesonephros, the lower ligament transforms into the gubernaculum testis, which plays a role in testicular descent. In the inguinal region, at the attachment site of the gubernaculum testis, a peritoneal outpouching forms, designated as the processus vaginalis.

By the 5th month of fetal development, the testis is located near the deep inguinal ring. During the 7th month of intrauterine development, the testis passes through the Inguinal Canal, reaching the Scrotum by the 8th month. At birth, the testis must occupy its position in the scrotum, which serves as one of the indicators of fetal maturity. If the testis is retained in the Abdominal cavity near the internal opening of the inguinal canal, an anomaly known as cryptorchidism occurs, requiring surgical intervention.

Descending caudally retroperitoneally into the scrotum, the testis wraps a layer of peritoneum around itself. In anatomy, this peritoneal layer is termed the visceral layer of the tunica vaginalis testis (tunica vaginalis propria). The remaining portion of the peritoneal sac lining the scrotal cavity is called the parietal layer. Between the parietal and visceral layers of the processus vaginalis lies a slit-like space, which may serve as a site for fluid accumulation during inflammatory conditions of the testis (such as orchitis, hydrocele, etc.). After the completion of testicular descent into the scrotum, the inguinal canal connecting the abdominal cavity to the scrotum closes; however, in 50% of cases, its internal opening remains incompletely closed, leading to the formation of inguinal-scrotal hernias (hernia scrotalis).