Chest Radiology > Anatomy > Mediastinum & Lungs

Mediastinum and Lungs

The radiologist needs to know both the structures within the mediastinum forming the mediastinal margins and the lobes of the lungs forming the margins of the lungs along the mediastinum and chest wall. If a mass or pneumonia "silhouettes" (obscures) a part of the lung/mediastinal margin, the radiologist should be able to identify what part of the lung and what organ within the mediastinum are involved. The margins of the mediastinum are made up of the structures shown below. Trace the margin of the mediastinum with your eye all the way around the margin.  Think of the mediastinal structures that comprise this interface.  If the margin were abnormal you could diagnose the cause.


This image outlines the specific anatomy of the PA chest x-ray.


This image indicates the locations of each lung margin on chest x-ray.



Trace the margin of the lung with your eye in the image below thinking about what mediastinal structure and what lobe of the lung is present at this margin.


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