A number of structures pass by, above, and around the ureters on their path down from the kidneys to the bladder. In its upper part, the ureter travels on the psoas major muscle and sits just behind the peritoneum. As it passes down the muscle, it travels over the genitofemoral nerve. The inferior vena cava and the abdominal aorta sit to the midline of the right and left ureters, respectively. In the lower part of the abdomen, the right ureter sits behind the lower mesentery and the terminal ileum, and the left ureter sits behind the jejunum and the sigmoid colon. As the ureters enter the pelvis, they are surrounded by connective tissue, and travel backward and outward, passing in front of the internal iliac arteries and internal iliac veins. They then travel inward and forward, crossing the umbilical, inferior vesical, and middle rectal arteries. From here, in males, they cross under the vas deferens and in front of the seminal vesicles to enter the bladder near the trigone. In females, the ureters pass behind the ovaries and then travel in the lower midline section of the broad ligament of the uterus. For a short part, the uterine arteries travel on top for a short () period. They then pass by the cervix, traveling inward towards the bladder.