Figure 13. Testicular descent. Initially (left) the primitive gonad is located near the kidney, held by the cranial suspensory ligament (CSL) and the gubernaculum testis. Androgen-mediated dissolution of the CSL and insulin like factor 3 (INSL3) mediated swelling of the gubernaculum brings the testis to the internal orifice of the inguinal canal (center). Inguino-scrotal migration consists of the passage of the testis through the inguinal canal into the scrotum and is thought to be androgen-dependent (right).