The arterial vessel to each testis most often arises from the anterolateral surface of the aorta just below the renal artery, although one of the vessels may originate from the renal artery or one of its branches. The right testicular (spermatic) artery runs over the psoas muscle and inferior vena cava, anterior to the genitofemoral nerve, the ureter, and the pelvic part of the external iliac artery to meet the spermatic cord at the internal inguinal ring. The left testicular artery passes behind the inferior mesenteric artery and left colic artery but otherwise takes a course similar to that of the right artery. In 6% to 8% of cases, each artery may divide high on the cord into an inferior testicular artery and an internal testicular artery. This division may occur retroperitoneally, requiring careful dissection of the cord during orchiopexy and making microvascular transplantation for cryptorchidism difficult.