Review Question - QID 214893

A 65-year-old woman presents to the office with a 1-week history of back pain. She states that the pain began after helping her daughter move into her apartment a week ago and is worsened with any kind of activity. The pain does not improve with rest. Her medical history is significant for diverticulosis. Her surgical history is notable for a hysterectomy she had 25 years ago for severe uterine prolapse after her fifth child. On physical exam, she complains of tenderness to palpation at the seventh thoracic vertebrae. She has 2+ knee and ankle jerk reflexes, and the remainder of her physical exam is normal. Which of the following is the most likely diagnosis?