ABC’s of Interpreting Chest X-Rays!

I’m sure I wasn’t alone the first time someone showed me a chest x-ray and asked me to interpret.  I believe “FML” was the first thing to hit my brain.

So, let me help you not have the FML moment when it comes to looking at chest x-rays.  The picture below is quite detailed and can be overwhelming.  What I am going to review is much more simple; but, it doesn’t hurt to take a peak at the image below just so you have some orientation.


ABC’s of Chest X-Rays

A: Airway/Assessment of Quality

I’ve seen both written for the letter “A”.

Airway: make sure the airway is patent and is not deviating to one side or the other which might indicate a tension pneumothorax.

Obvious tracheal deviation.

Adequate Study: 

  • Position.  Make sure the study was not taken with the patient turned more to one side than the other.
  • Lung expansion.  10-11 ribs should be visible in each of the lung fields to be considered adequate.
  • Penetration (too dark/too light)  Can you see the spaces between vertebrae?  That means its a good study!
Example of how to properly count ribs.  There are 8 visible.  Finding a study with 10 visible was proving difficult.

B: Bones

Don’t forget there are bones to look at in a CXR!  Although in most cases its secondary and in the background make sure there are no clavicle or rib fractures or shoulder dislocations.  You never know what you might find.  So take a quick glance at the bones.  Start from the top and work your way down to stay organized and on track.  There can be a lot going on in a CXR.

C: Cardiac

What does the patient’s cardiac silhouette look like? The size of the heart should be <50% of the PA film dimension.

Outline of cardiac silhouette.


D: Diaphragm

Look for position (right will always be slightly higher than the left due to liver), make sure there isn’t free air or maybe flattening due to emphysema. Make sure the costophrenic angles are both visible.

Example of how the diaphragm should appear on each side of the lung fields with the right slightly higher.  Also visualized is the gastric air bubble (which is normal).

E: Effusions

Simple.  Presence or lack of pleural effusions.

Obvious right pleural effusion with what looks like tracheal deviation to right likely due to the large effusion on right.


F: Fields & Fissures

I’m not going to pretend like I can appreciate a lung fissure on an x-ray.  I am definitely NO radiologist.  Fields stands for lung fields.  Basically what do you see in the lungs.  Take a look around for infiltrates, kerley B lines, pulmonary congestion, granulomas, pneumothorax, masses, etc.  Symmetry is your best friend in radiology–make sure both lung fields look roughly the same in vascular markings, etc.

Potential findings when looking at the lung fields.

G: Great Vessels

The Aortic knob is probably the only thing I can really appreciate well on a chest x-ray.  Make sure the aorta in it’s entirety isn’t obviously out of proportion.



H: Hila & Mediastinum

Look for widening of the mediastinum which is a pearl for Aortic Dissection or Hilar Lymphadenopathy as seen in Sarcoidosis. image

I: Instruments/Impression

Instruments stands for anything implanted in the patient such as pacemakers, etc.Summarize all of your findings as concisely as possible and to the best of your ability!

ICD visualized on Chest X-Ray.

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