Axial, sagittal, coronal
Read Your Scan Editorial Team·Last updated
Written from published radiology references and reviewed for plain language. Not written or signed by a physician, and not a diagnosis. How we write these pages →
In plain language
The three directions a scan is sliced in: axial cuts across the body like slices of a loaf, sagittal splits left from right, coronal separates front from back. A finding is often described in each, because some things only look like themselves from one angle.
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Where you'll see this
The technique section, and wherever a finding is located.
Your report may word it “Transverse”, “Planes” or “Multiplanar”. These mean the same thing.
Questions worth asking your doctor
- Did this scan use the right technique to answer my question?
- Would contrast, or a different sequence, show something this one could not?
- Do I need another scan, or is this one enough?
How often does this turn up?
These three words appear on nearly every cross-sectional report, because a scan is not one picture but a stack of slices and the radiologist has to say which way the stack was cut. Axial slices cut across the body like slices through a loaf, sagittal splits left from right, coronal separates front from back. Most studies acquire more than one, and a finding is usually described on the plane where it shows best.
Does it mean something is wrong?
Nothing at all. This is pure geography — the three words say where the camera was, not what it found. They carry no clinical meaning on their own, and a report describing something "on the axial images" is telling the next reader where to look rather than saying anything about how serious it is.
What to do with it
The useful thing is that these words let you find the finding yourself if you have the images: a report placing something on axial slice 24 is giving you a coordinate. One genuine trap is worth knowing. On axial images the convention is to view the patient from the feet upwards, so the patient’s right appears on the left of your screen. It is the most common way a non-radiologist misreads which side a finding is on — and it is also why software reading a flat screenshot, with no access to the orientation stored in the scan file, gets left and right wrong so often.
Frequently asked questions
- Which plane is best for what?
- Broadly: axial for cross-sections of the brain, chest and abdomen, sagittal for the spine because it shows the whole column from the side, and coronal for comparing left with right. Radiologists read them together rather than choosing one, because a structure that is ambiguous on one plane is often obvious on another.
- Why does the left side of the image show my right side?
- Because axial images are conventionally displayed as if you were looking at the patient from the feet up, which mirrors left and right. Radiologists work with this every day; people reading their own images usually do not know it, and it is the most frequent reason someone thinks a finding is on the wrong side.
- Does more planes mean a better scan?
- Not by itself. Which planes are acquired depends on what the scan is looking for, and adding planes costs time in the scanner. A well-chosen two-plane study answers its question better than a scattergun set that leaves the patient in the machine longer.
How the scan was taken
Where this word comes up
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