The mediastinum is best described as which anatomical region?

• A. Area between the lungs containing the heart, aorta, venae cavae, esophagus, and trachea.
• B. The region around the diaphragm.
• C. The space inside the lungs.
• D. The membrane surrounding the lungs.

Answer: (A)

The mediastinum is the central compartment of the thoracic cavity, situated between the lungs. It extends from the superior thoracic aperture down to the diaphragm and houses the heart and great vessels (like the aorta and venae cavae), the esophagus, and the trachea, among other structures. This matches the description of the area between the lungs containing the heart, aorta, venae cavae, esophagus, and trachea.

It isn’t the region around the diaphragm (that describes the lower boundary of the thorax), nor the space inside the lungs (the pulmonary airways and parenchyma), nor the membrane surrounding the lungs (the pleura).