A 38-year-old woman from Mumbai undergoes a routine pelvic ultrasound for evaluation of infertility. The sonographer notes that the left ureter is dilated (8 mm) and appears to cross anterior to the left ovarian vessels near the pelvic brim. The patient is asymptomatic with normal renal function. The radiologist suspects a crossing vessel syndrome causing mild ureteric compression. Which of the following anatomical relationships best explains the potential for ureteric compression by the ovarian vessels in this patient?