Testicular descent

Last revised by Yaïr Glick on 27 Aug 2023

Testicular descent occurs after the fourth month of fetal life. The testes are derived from the gonadal ridge medial to the mesonephric ridge of the intermediate cell mass. An elongated diverticulum of the peritoneal cavity, the processus vaginalis bulges through the inguinal canal into the scrotum and descends into it, then, in turn, the testis descends into the pouch that has been formed by the processus vaginalis. Normally, the cranial part of the processus vaginalis obliterates and the caudal part that envelops the testis and the tunica albuginea becomes the tunica vaginalis

The timing of descent is as follows:

  • 4th fetal month - near the deep inguinal ring

  • 7th fetal month - within the deep inguinal ring

  • in the next few days to weeks, it descends into the scrotum

Failure of the testes to descend may result in cryptorchidism. Failure of the obliteration of the whole processus vaginalis leads to the formation of an indirect inguinal hernia. Persistence of part of the processus leads to the formation of a hydrocele (of the cord or testis). 

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