Ischemic colitis

A 56-year-old man begins complaining of abdominal pain while recovering in the post-anesthesia care unit after undergoing surgical repair for a ruptured abdominal aortic aneurysm. The procedure was complicated by blood loss and hypotension. The patient states the current pain is 6 out of 10 in severity. Past medical history is notable for atherosclerosis and peripheral vascular disease. The patient has a 35-pack-year smoking history. His temperature of 37.6°C (99.7°F), blood pressure of 118/70 mmHg, and pulse of 78/min. Localized abdominal pain is elicited with light palpation over the area in question. The surgical site is dry and healing. Which of the following portions of the colon is most likely affected in this patient?