Widened mediastinum


  • Diagnosed on plain radiography of the chest
  • Mediastinal width >8cm is abnormal
  • Potential causes include:
    • AP projection (Mediastinal structures further away from imaging plate)
    • Thoracic aortic aneurysm
    • Aortic dissection/rupture
    • Mediastinal mass


  • Mediastinum is divided into superior and inferior compartments, the latter further subdivided into anterior, middle and posterior compartments.[1]
Anatomy and contents of the mediastinum[2]

Mediastinal Masses

  • Anterior
    • Retrosternal goiter
    • Thymoma
    • Germ-cell tumor
    • Lymphadenopathy (lymphoma)
  • Middle
    • Aortic arch aneurysm
    • Dilated pulmonary artery
    • Tracheal lesion
  • Posterior
    • Esophageal lesions
    • Hiatal hernia
    • Descending aortic aneurysm
    • Paraspinal abscess


CXR showing widened mediastinum and porminent aortic knob in nontraumatic thoracic aortic dissection
Blunt thoracic aortic injury on CXR showing widened mediastinum

See Also

External Links


  1. Whitten CR, Khan S, Munneke GJ, Grubnic S. A diagnostic approach to mediastinal abnormalities. Radiographics. 2007;27(3):657–671. doi:10.1148/rg.273065136.
  2. Faiz, O., & Moffat, D. (2002). Anatomy at a glance. Malden, MA: Blackwell Science.