Radiology · single question
What is the purpose of the small ruler/scale that appears on a lateral cephalometric radiograph?
Show answer and explanation
Correct answer: B. It allows correction for image magnification, calibrating linear measurements made on the radiograph to true life-size values
Because a cephalometric radiograph is a projected (magnified) image, a ruler of known length included in the image allows the clinician/software to calculate and correct for the magnification factor, ensuring linear measurements reflect true anatomic dimensions.