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How to Read & Interpret X-Rays

Knowing how to properly read and interpret an x-ray seems like a basic and minor process, but it provides the foundation for proper diagnosis and treatment of a multitude of conditions and can jumpstart treatment on time sensitive ailments. Knowing how to accurately read an x-ray will help solidify you and your practice as a trusted, first resort for patients experiencing medical issues beneath the surface. We could write a book on x-ray interpretation as it pertains to the different parts of the body, but with this article we’d like to just touch upon x-ray basics.

X-Ray Densities

The first principle behind knowing how to read an x-ray is knowing how different parts of the body will absorb an x-ray. This absorption falls into three basic categories and they are:

  • Bone – appears light grey or white because it absorbs a high percentage of the x-ray (metal is pure white)
  • Tissue – appears a greyish color because it absorbs some but not a majority of the x-ray (water or fat, for example)
  • Air – appears black because it absorbs a very low percentage of the x-ray (gas, for example)

Second is determining whether the x-ray penetrated through the patient from the front or the back. A posteroanterior(PA) x-ray comes from the back while an anteroposterior(AP) x-ray comes from the front.

X-Ray Margins

When interpretting an x-ray, all of the bones and organs should fall within a certain range of size and shape. In x-ray jargon, this means that margins should be sharp. Using a ruler or any other measuring device will help you confirm or deny if a patient’s margins appear sharp and normal. Abnormal margins could mean the presence of an abnormal growth. If you were looking at a chest x-ray, a normal, healthy chest would include a cardiac silhouette occupying less than half of the chest’s width.

X-Ray Abnormalities

Once you’ve familiarized yourself with what looks standard on an x-ray, familiarizing yourself with abnormalities is the next step to proper x-ray interpretation. Take an x-ray of the chest, for example. All of a patient’s vital organs should appear as a dark grey color. Large spots of black where the lungs should be or large spots of white signify excess gas or an abnormal growth, respectively.

From a broken bone standpoint, you could expect bone lesions to appear whiter than the bone itself, while breaks and fractures would appear darker to explain the increased amount of air occupying the space.

At its core, x-ray interpretation boils down to finding normalities from which to base your readings on. Symmetry of bones and organs is especially important. Once those baseline measurements and observations are made, an x-ray can be properly interpreted to best diagnose the patient. Join us in our X-Ray Interpretation CME course taught by Dr. Mark Needham to learn more about x-ray interpretation and how it can set your practice apart from the rest.