The genitofemoral nerve may link testicular inguinoscrotal descent with congenital inguinal hernia

The genitofemoral nerve (GFN) hypothesis for inguinoscrotal testicular descent proposes that calcitonin gene-related peptide (CGRP), released from the genitofemoral nerve, controls the migration of the gubernaculum from the inguinal region to the scrotum between 26 and 40 weeks of gestation. The processus vaginalis provides a channel through which the testis descends from the abdomen to the scrotum. Following descent of the testis the processus vaginalis undergoes luminal obliteration and disappearance between the internal inguinal ring and the upper pole of the testis. The mechanism underlying closure of the processus is unknown and failure for it to occur normally results in congenital inguinal hernia, scrotal hydrocele and possibly even an 'ascending' testis. Recent work in our laboratory suggests that CGRP, released from the genitofemoral nerve, may cause fusion and disappearance of the processus vaginalis. We propose that abnormalities in the GFN link a spectrum of disorders encompassing congenital undescended testis, inguinal hernia, scrotal hydrocele and ascending testis.