A 19-year-old female college student presents to the emergency department at 10:30 PM on a Friday night with severe left-sided flank and pelvic pain. While she has never had similar pain, she states that she thinks she has a kidney stone. The pain started in her mid-back about a week ago and then subsided and now the pain has increased and moved interiorly along her flank and also extends down into her labia majora. She is taking birth control pills, but is not currently sexually active. She is having her period, but denies the pain is menstrual. Abdominal and pelvic CT are ordered. What two specific locations will one look for in the CTs for obstructing calculi?