The mediastinum is the area between the right and left lungs, bounded by the medial-parietal pleura. Mediastinal diseases can be difficult to detect on chest x-ray because most diseases are of soft tissue density and are surrounded by other soft tissue structures. Mediastinal lesions may cause focal or diffuse widening; displace, compress, or invade adjacent structures; or cause an apparent silhouette sign with adjacent structures.
(Courtesy of Dr. Melissa Wein, Medical College of Wisconsin, Milwaukee.)
(Courtesy of Dr. Melissa Wein, Medical College of Wisconsin, Milwaukee.)
