Final answer:
The nurse should expect to hear a bruit over the middle upper abdomen when obtaining the health history of a patient with an abdominal aortic aneurysm.
Step-by-step explanation:
When obtaining the health history of a patient with an abdominal aortic aneurysm, the nurse should expect a bruit heard over the middle upper abdomen. A bruit is an abnormal sound caused by turbulent blood flow through a narrowed artery, and it can be heard with a stethoscope. This finding is significant because it indicates the presence of an aneurysm in the abdominal aorta.