The mediastinum is located which of the following?

• A. Behind the sternum, between the lungs
• B. In front of the sternum
• C. Within the left atrium
• D. In the abdominal cavity

Answer: (A)

The mediastinum is the central compartment of the thoracic cavity, and it sits between the two lungs. It lies behind the sternum and extends from the superior thoracic inlet down to the diaphragm, with the sternum at the front and the vertebral column at the back. This space contains the heart and great vessels, as well as the trachea, esophagus, and other structures.

So describing it as behind the sternum, between the lungs, matches its actual location. Describing it as in front of the sternum would place it anterior to the sternum, which isn’t correct, and the left atrium is a heart chamber, not the location of the mediastinum, while the abdominal cavity is well below the diaphragm in the abdomen.