[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Embryology](https://durgical.com/en/embryology/) › [Urogenital system](https://durgical.com/en/embryology/#a-urogenital) › Gonads and the descent of the testis [Embryology](https://durgical.com/en/embryology/) · [Urogenital system](https://durgical.com/en/embryology/#a-urogenital) # Gonads and the descent of the testis - Process Testes and ovaries start high in the abdomen; the testis travels down to the scrotum guided by a cord called the gubernaculum. Updated 2026-11-01 **See it in 3D:** [Ovaries](https://durgical.com/en/anatomy/ovary/) · [Scrotum](https://durgical.com/en/anatomy/scrotum/) · [Inguinal canal](https://durgical.com/en/anatomy/inguinal-canal/) · [Testicular arteries](https://durgical.com/en/anatomy/testicular-artery-pelvis/) · [Testicular veins and pampiniform plexus](https://durgical.com/en/anatomy/testicular-vein-pampiniform-plexus/) · [Spermatic cord](https://durgical.com/en/anatomy/spermatic-cord/) · [Testicular vessels](https://durgical.com/en/anatomy/testicular-artery/) · [Ovarian ligament](https://durgical.com/en/anatomy/proper-ovarian-ligament/) · [Round ligament of uterus](https://durgical.com/en/anatomy/round-ligament-of-uterus/) ## Key points - Primordial germ cells: from the epiblast, via the yolk sac wall and the dorsal mesentery to the gonadal ridge (weeks 4–6). - Transabdominal phase (weeks 8–15): driven by INSL3 from Leydig cells and growth of the gubernaculum. - Inguinoscrotal phase (from about week 26): androgen-dependent; almost all testes are in the scrotum at birth. - Testicular artery: arises from the aorta at lumbar level; testicular lymph drains to para-aortic nodes. - In females the gubernaculum forms the ovarian ligament and the round ligament of the uterus. ## What it is The gonads form in the gonadal ridge beside the mesonephros, from coelomic epithelium, mesenchyme and germ cells that arrive from the yolk sac. The testis descends in two phases, abdominal and inguinoscrotal, dragging its vessels down from the lumbar region. That journey explains cryptorchidism, indirect inguinal hernia, hydrocele and why testicular cancer drains to the para-aortic nodes. ## Key facts - Testis: medullary sex cords become the seminiferous cords (solid until puberty) and the rete testis. - The tunica albuginea separates the cords from the surface epithelium: the hallmark of the testis. - Ovary: cortical cords surround the oogonia and form primordial follicles. - Primary oocytes arrest in prophase of meiosis I before birth. - The processus vaginalis runs ahead of the testis into the inguinal canal and then closes, leaving the tunica vaginalis. ## Structure - Coelomic epithelium: Sertoli cells (testis) and granulosa cells (ovary). - Mesenchyme: Leydig cells (testis) and theca cells (ovary). - Primordial germ cells: spermatogonia or oogonia. - Gubernaculum: mesenchymal cord from the lower pole of the gonad to the labioscrotal folds. ## Step by step - The gonadal ridge appears on the posterior abdominal wall, medial to the mesonephros. - Primordial germ cells arrive and sex cords form. - With SRY a testis forms; without it, an ovary. - The gubernaculum grows and the cranial suspensory ligament regresses: the testis reaches the deep inguinal ring. - The processus vaginalis forms, an outpouching of peritoneum into the inguinal canal. - Under androgens the testis passes through the inguinal canal and reaches the scrotum in the third trimester. - The processus vaginalis obliterates, leaving only the tunica vaginalis around the testis. ## Markers - SRY - SOX9 - INSL3 - AR - WT1 - SF1 ## Clinical notes - If descent stops: cryptorchidism, more common in preterm babies. - If the processus vaginalis stays open: indirect inguinal hernia or communicating hydrocele. - Testicular cancer spreads to para-aortic, not inguinal, nodes because its vessels are lumbar in origin. - Varicocele is more common on the left: the left testicular vein drains at a right angle into the left renal vein. ## Memory aid “The testis is a traveller born by the kidney who packs its own luggage”: it carries lumbar arteries, veins and lymph, and leaves the door open if the processus vaginalis fails to close. ## Test yourself Think of the answer, then tap the question to see it. ## Which hormone drives the transabdominal phase of testicular descent, and which cell makes it? INSL3 (insulin-like factor 3), made by Leydig cells; it acts on the gubernaculum. ## Why does testicular cancer spread to the para-aortic lymph nodes? The testis forms in the lumbar region and keeps the vessels and lymphatic drainage of that origin as it descends. ## What does the gubernaculum become in females? The ovarian ligament and the round ligament of the uterus. ## Where do primordial germ cells come from and how do they reach the gonad? From the epiblast; they sit in the yolk sac wall and migrate along the dorsal mesentery of the hindgut to the gonadal ridge in weeks 4–6. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/embryology/gonads-and-the-descent-of-the-testis/) ## See it in 3D The structures of Durgical's 3D anatomy where it is found. - [Ovaries](https://durgical.com/en/anatomy/ovary/) - [Scrotum](https://durgical.com/en/anatomy/scrotum/) - [Inguinal canal](https://durgical.com/en/anatomy/inguinal-canal/) - [Testicular arteries](https://durgical.com/en/anatomy/testicular-artery-pelvis/) - [Testicular veins and pampiniform plexus](https://durgical.com/en/anatomy/testicular-vein-pampiniform-plexus/) - [Spermatic cord](https://durgical.com/en/anatomy/spermatic-cord/) - [Testicular vessels](https://durgical.com/en/anatomy/testicular-artery/) - [Ovarian ligament](https://durgical.com/en/anatomy/proper-ovarian-ligament/) - [Round ligament of uterus](https://durgical.com/en/anatomy/round-ligament-of-uterus/) ## Related - [Sex determination: SRY, anti-Müllerian hormone and testosterone](https://durgical.com/en/embryology/sex-determination-sry-anti-mullerian-hormone-and-testosterone/) - [Genital ducts: Wolffian (mesonephric) and Müllerian (paramesonephric)](https://durgical.com/en/embryology/genital-ducts-wolffian-and-mullerian/) - [Cryptorchidism](https://durgical.com/en/embryology/cryptorchidism/) - [Processus vaginalis: hydrocele and indirect inguinal hernia](https://durgical.com/en/embryology/processus-vaginalis-hydrocele-and-indirect-inguinal-hernia/) - [Gametogenesis: spermatogenesis and oogenesis](https://durgical.com/en/embryology/gametogenesis-spermatogenesis-and-oogenesis/) - [Ovarian cycle, ovulation and the corpus luteum](https://durgical.com/en/embryology/ovarian-cycle-ovulation-and-the-corpus-luteum/) - [Differences of sex development: CAH, AIS and 5α-reductase](https://durgical.com/en/embryology/differences-of-sex-development-cah-ais-and-5-reductase/) ## Related conditions - [Cryptorchidism (undescended testis)](https://durgical.com/en/conditions/cryptorchidism/) - [Hydrocele](https://durgical.com/en/conditions/hydrocele/) - [Inguinal hernia](https://durgical.com/en/conditions/inguinal-hernia/) - [Testicular cancer](https://durgical.com/en/conditions/testicular-cancer/) [← All of embryology](https://durgical.com/en/embryology/) Educational content on embryonic development; not a guide to prenatal diagnosis or to medicines in pregnancy and no substitute for a health professional's advice. No doses are given. Sources: [Embryology, Testicle - StatPearls - NCBI Bookshelf](https://www.ncbi.nlm.nih.gov/books/NBK557763/) (StatPearls Publishing (NCBI Bookshelf), 2023); [Embryology, Sexual Development - StatPearls - NCBI Bookshelf](https://www.ncbi.nlm.nih.gov/books/NBK557601/) (StatPearls Publishing (NCBI Bookshelf), 2023). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/embryology/gonads-and-the-descent-of-the-testis/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/embryology/gonads-and-the-descent-of-the-testis/