Descent of the testis in the fetal calf. A summary of the anatomy and process.

The descent of the testis in the fetal calf is reviewed, and the role in that process of the swelling reaction of the gubernaculum testis is discussed. The testes of 30 Dutch Friesian fetuses were examined by dissection and light microscopy of sections prepared from chemically and frozen-fixed specimens. The gubernaculum remains unattached to the scrotal fasciae until descent is completed. Shortening of the intra-abdominal gubernaculum and displacement of the testis begins at fetal week 11; the swelling reaction of the gubernaculum occurs between weeks 14 and 15. The testis is at the deep inguinal ring by week 15, and by week 20 it is in the scrotal position and the gubernaculum has regressed. It is proposed that the swelling of the gubernaculum dilates the vaginal ring and enlarges the inguinal canal. The clinical importance of these anatomical relationships and changes is discussed.