Widened mediastinum 2022-12-10T17:43:55Z Mediastinal widening This feature can be ascertained by plain chest radiography. A wide mediastinum has many causes which include thoracic aortic aneurysm of the ascending and proximal descending aorta, aortic dissection of ascending and proximal descending aorta, unfolding of the aorta, traumatic aortic rupture, hilar lymphadenopathy, mediastinal masses, mediastinitis, cardiac tamponade, and fractured ribs or thoracic vertebrae. Abnormal increase in the width of the mediastinum, often defined as being greater than 6 to 8 cm. Abnormal mediastinum morphology